Lpic Study Guide

Front 1

What does the 'netstat -in' command do?

Back 1

It shows the state of all configured network interfaces, using numeric values for users, hosts and ports

Front 2

What command shows the state of all configured network interfaces, using numeric values for hosts?

Back 2

netstat -i --numeric-hosts
OR
netstat -in

Front 3

What does the "netstat -a" command do?

Back 3

The default operation of netstat is to show sockets. The -a argument tells netstat to show "all". It's not very much different to running netstat alone.

Front 4

What command shows the state of all network sockets?

Back 4

netstat -a

Front 5

What command shows statistics for a the TCP protocol?

Back 5

netstat -st

Front 6

What does the 'netstat -s' command do?

Back 6

It shows summary statistics for each network protocol.

Front 7

What command shows statistics for each network protocol?

Back 7

netstat -s

Front 8

What is 'PMTU'?

Back 8

Path Maximum Transmission Unit.

Explanation: When a host transmits packets across multiple networks to another host the packets will become fragmented if their size is greater than the smallest MTU of any network in the path. Packet fragmentation can result in reduced network performance.

Summary: Path Maximum Transmission Unit is the smallest MTU along an entire network path.

Front 9

What is SmokePing?

Back 9

A tool used to monitor network latency using RRDTool to store and display graphs.

Front 10

What tool is used to monitor network latency using RRDTool to store and display graphs?

Back 10

SmokePing

Front 11

What is the file /etc/sysctl.conf used for?

Back 11

It is a configuration file for setting kernel parameters at runtime (eg: TCP buffer size, swappiness, security).

You can force the kernel to re-read the file using the command:

sysctl -p

You can show all current values using this command:

sysctl -a

Front 12

What configuration file is used to set kernel parameters (like TCP buffer size, swappiness etc)?

Back 12

/etc/sysctl.conf

Front 13

What does the 'sysctl -p' command do?

Back 13

It loads settings from /etc/sysctl.conf and modifies kernel parameters at runtime. The sysctl command can read or write system configuration.

Front 14

What command loads settings from /etc/sysctl.conf and modifies kernel parameters at runtime?

Back 14

sysctl -p

Front 15

What is the purpose of the pseudo filesystem /proc ?

Back 15

/proc is the kernel's status repository. It contains pseudo files that show information about the running system.

Front 16

What does the pseudo file /proc/interrupts contain?

Back 16

It contains information about IRQ assignments on a running system.

Front 17

Which pseudo file contains details of the IRQ assignments on a running system?

Back 17

/proc/interrupts

Front 18

What does the pseudo file /proc/ioports contain?

Back 18

It contains information about IO ports on a running system.

Front 19

What pseudo file contains details of available IO ports on a running system?

Back 19

/proc/ioports

Front 20

What does the pseudo file /proc/dma contain?

Back 20

It contains information about DMA (Direct Memory Access) devices.

Front 21

What is the pseudo file that contains DMA (Direct Memory Access) device information.

Back 21

/proc/dma

Front 22

Briefly describe Cylinder Head Sector (CHS) disk geometry.

Back 22

IDE disks are formated into 512byte sectors, arranged in concentric circles (each called a cylinder) which is written to by a head. This disk geometry allows for up to 65526 cylinders, 16 heads and 255 sectors / track. Maximum capacity is 137GB

Front 23

What is LBA (Logical Block Address)?

Back 23

To overcome the limits of CHS disk geometry, ATA-2 standards implemented the LBA addressing system for disk drives.

Front 24

What does the 'hdparm -l' command do?

Back 24

It show hard disk parameters.

Front 25

What command shows hard disk parameters for /dev/sda?

Back 25

hdparm -l /dev/sda

Front 26

What does the following command do?
dmesg | grep -i irq

Back 26

It shows all interrupts found during boot

Front 27

What command shows all interrupts found by the kernel during the boot process?

Back 27

dmesg | grep -i irq

Front 28

What does the following command do?
dmesg | grep -i dma

Back 28

It shows DMA capable devices found by the kernel on boot.

Front 29

What command shows DMA capable devices found during the boot process?

Back 29

dmesg | grep -i dma

Front 30

What does the following command do?
dmesg | grep "[hs]d[a-z]"

Back 30

It shows all hard disks found by the kernel during boot.

Front 31

What command shows all hard disks found during the boot process?

Back 31

dmesg | grep "[hs]d[a-z]"

Front 32

What does the 'lspci' command do?

Back 32

It lists all PCI devices.

Front 33

What command lists all PCI devices?

Back 33

lspci

Front 34

What is the file /etc/modprobe.conf used for?

Back 34

It stores the configuration of kernel modules on 2.6+ kernels

Front 35

Which file stores the configuration of kernel modules on 2.6+ kernels?

Back 35

/etc/modprobe.conf

Modern systems use a directory called /etc/modprobe.d which contains separate files different device classes.

Front 36

What does the 'lsmod' command do?

Back 36

It shows the status of modules in the Kernel.

Front 37

What command shows the status of modules in the Kernel?

Back 37

lsmod

Front 38

What is sndconfig?

Back 38

Sndconfig is a command written by RedHat for configuring sound devices. It uses isapnp. It does not detect resource conflicts.

Front 39

What command can be used to configure sound devices?

Back 39

sndconfig

Front 40

What /dev file represents the first CD or DVD device?

Back 40

/dev/scd0 or /dev/sr0

Front 41

What /dev file represents the first hard disk device?

Back 41

/dev/sda

Front 42

What /dev file represents the first tape device?

Back 42

/dev/st0

Front 43

What does the 'scsi_info' command do?

Back 43

Shows the details of the 'real' device that corresponse to /dev/sda.

Front 44

What command shows the details of the 'real' device that corresponse to /dev/sda?

Back 44

scsi_info /dev/sda

Front 45

What are 'SCSI Generic drivers'?

Back 45

SCSI Generic drivers are generally used to handle devices that aren't covered by sd and st drivers (enclosuires, cd writers, scanners). When sg drivers are used, additional information is available in /proc/scsi/sg. There will also be devices such as /dev/sg0, /dev/sg1 etc, which correspond to other devices such as /dev/sr0

Front 46

What does the 'sg_map' command do?

Back 46

It shows the mappings between 'sg' name and device name for SCSI devices.

Front 47

What command provides a map between 'sg' name and the device name for SCSI devices?

Back 47

sg_map

Front 48

What does the 'sginfo' command do?

Back 48

This command interrogates devices directly using the "SCSI Generic" driver. Because this command talks to the devices, it must be run as root.

Front 49

What command interrogates devices using the "SCSI Generic" driver?

Back 49

sginfo

Note: The sginfo command talks to devices directly, so it must be run as root. The scsi_info command doesn't interrogate devices, but reads /proc files to obtain details; it can be executed without root privileges.

Front 50

How many devices can a USB hub support? What is the total number of devices on a root hub?

Back 50

A USB hub can support 7 devices [some of which may be hubs]

A root hub supports up to 127 devices in total.

Front 51

What is the purpose of the 'USB Bus Interface layer'?

Back 51

The USB Bus Interface layer provides physical, signaling, and packet connectivity between hosts and devices, providing data transfer between the host and devices.

Front 52

Which USB layer provides physical, signaling and packet connectivity between hosts and devices?

Back 52

The USB Bus Interface Layer

Front 53

What is the purpose of the 'USB Device layer'?

Back 53

The USB Device layer is used by the system software to do generic USB operations with a device over the bus. This allows the host to determine characteristics of the device, including device class, vendor name, device name, power requirements, and many capabilities such as device speed or USB level supported.

Front 54

Which USB layer is used by the system to do generic operations with devices over the bus (including querying its characteristics and requirements)?

Back 54

The USB Device Layer

Front 55

What is the purpose of the 'USB Function layer'?

Back 55

This USB layer provides additional capabilities that are specific to the device. Matched host and device software layers permit use device-specific functions.

Front 56

Which USB layer provides additional capabilities that are specific to devices?

Back 56

The USB Function layer.

Front 57

What speed do USB 1.0 and 1.1 operate at?

Back 57

12Mbps

Front 58

What speed does USB 2.0 operate at?

Back 58

480Mbps

Front 59

What does the following command do?
lspci | grep -i usb

Back 59

It lists all USB controllers on the system, telling you what USB version is supported on each.

Front 60

What command shows USB controllers?

Back 60

lspci | grep -i usb

Note: This will tell you if the system supports USB 2 / 3. Devices connected to the USB controllers will not appear. For that you need lsusb.

Front 61

What does the pseudo file /proc/bus/usb/devices contain?

Back 61

It contains information about USB root hubs attached to the system.

Front 62

Which pseudo file shows information about USB devices attached to the system

Back 62

/proc/bus/usb/devices

Front 63

What does the 'lsusb -t' command do?

Back 63

It shows shows a tree view of USB devices.

Front 64

What command shows a tree view of USB devices

Back 64

lsusb -t

Front 65

What does the 'lsusb -v' command do?

Back 65

It shows verbose information about usb devices.

Front 66

What command shows verbose information about usb devices?

Back 66

lsusb -v

Front 67

What does the 'usbmgr' command do?

Back 67

It is used to handle hot plugging of USB devices by loading/unloading USB kernel modules when devices connect into or disconnect from a USB hub.

Front 68

What does the 'hotplug' command do?

Back 68

It is used to handle hot plugging of USB devices

Front 69

What commands handle hot plugging of USB devices?

Back 69

hotplug or usbmgr

Front 70

What is the IDE drive partition limit?

Back 70

63 partitions.

Front 71

What is the SCSI drive partition limit?

Back 71

15 partitions

Front 72

What does the pseudo file /proc/ide/sda/geometry contain?

Back 72

It shows the capacity of the first IDE disk in terms of Cylinders/Heads/Sectors.

The file /proc/ide/sda/capacity shows the capacity in LBA format.

Front 73

Which pseudo file shows the nomimal geometry of the first SCSI disk?

Back 73

/proc/ide/sda/geometry

Front 74

Where is the partition table located?

Back 74

The MBR (master boot record) holds the partition table and bootstrap code. It's the first 512kb of the active disk.

Front 75

Where is the MBR located?

Back 75

On the first sector of the disk

Front 76

What are the 3 partition types?

Back 76

1. Primary - only 4 can exist
2. Extended - only 1 can exist. It is a container for logical partitions
3. Logical

Front 77

Run through the boot process of a Linux system...

Back 77

1. The BIOS boot code is executed, performing POST and loading the MBR.
2. The MBR boot code find the active partition and loads the first sector (partition boot record)
3. The 'Stage 2 boot loader' proceeds directly to load the kernel.
4. The Linux kernel continues to start the system, referring to /etc/inittab

Front 78

What is LILO? What configuration file does it use?

Back 78

LInux LOader is a smart bootloader, once the default on many distros, but has been dropped from many in favour of GRUB.

It uses /sbin/lilo to write a stage 1 boot record and create a /boot/map file using the configuration information from /etc/lilo.conf

Any time the config file changes, lilo must be executed again, unlike GRUB which reads the config file during each boot.

Front 79

What does the 'lilo -u' command do?

Back 79

It uninstalls lilo and restores previous boot record

Front 80

What does the 'lilo -R' command do?

Back 80

It sets lilo to automatically boot the specified system on the next reboot only.

Front 81

Briefly describe GRUB, where it keeps its configuration, and where it can be installed.

Back 81

GRand Unified Bootloader is the most common Smart Bootloader. It is installed into the MBR or into a partition boot record. It can be installed on CDs, USB keys or floppy disks.

Front 82

How do you install GRUB to a floppy disk?

Back 82

1. Unmount the floppy disk
2. grub-install /dev/fd0

[Note: Unmounting partitions on an IDE or SCSI disk is not necessary as they do not mount the MBR!]

Front 83

What does the following command do?
tar -jxf file.tar.bz2

Back 83

Untars a tar file compressed with bzip2.

Front 84

What command untars a file compressed with bzip2?

Back 84

tar -jxf file.tgz

Front 85

What does the following command do?
'tar -zxf file.tgz' do

Back 85

Untars a tar file that was compressed with gzip.

Front 86

What command untars a file that has been compressed with gzip?

Back 86

tar -zxf file.tgz

Front 87

What command is equivalent to 'zcat'?

Back 87

gunzip -c

Front 88

Which command is equivalent to 'gunzip -c'?

Back 88

zcat

Either command will gunzip a file to stdout.

Front 89

What do the 'unzip' command do?

Back 89

It decompresses .zip (PKZIP) files.

Front 90

What command decompresses .zip (PKZIP) files?

Back 90

unzip

Front 91

What does the following command do?
./configure --prefix /opt/new

Back 91

The configure script it is used to configure source code before compiling. The --prefix option specifies an installation path. [Default path is /usr/local on most distros.]

Front 92

When compiling source code, what is the function of the config.cache file?

Back 92

Before compiling the source code, you must run the configure script to specify compile options. The config.cache file stores the configuration for 'make' to use.

Front 93

After running ./configure in a source code directory which file stores the saved configuration?

Back 93

config.cache

Front 94

What are statically linked executables?

Back 94

These executables contain all the library functions that they need to execute. This makes them larger, but they have no dependencies.

Front 95

What type of executables contain all the library functions that they need to execute?

Back 95

Statically linked executables.

Front 96

What are Dynamically linked executables?

Back 96

They are small, incomplete programs which require functions from external shared libraries. This enables many programs to share common libraries, saving on disk space and memory.

Front 97

What type of executables are small incomplete programs which require functions from external shared libraries?

Back 97

Dynamically linked executables.

Front 98

What is the binary '/sbin/sln'?

Back 98

It is a statically linked version of the ln command. It is used when 'ln' fails due to dependency problems.

Front 99

What does the 'ldd' command do?

Back 99

It shows all shared libraries required by a program.

Important: ldd is actually a bash script that checks the binary's .interp ELF section to discover which loader it uses, and then runs one of these commands:

LD_TRACE_LOADED_OBJECTS=1 /bin/grep
LD_TRACE_LOADED_OBJECTS=1 /lib/ld-linux.so.2 /bin/grep

If a program is not handled by the default loader "ld-linux.so", and doesn't handle the LD_TRACE_LOADED_OBJECTS environment, ldd tries to discover which loader it uses. Unfortunately, it's easy to create a loader that instead executes the program.

If you are unfamiliar with the binary you are running ldd on, be very careful!

Front 100

What command shows all the shared libraries required by gedit?

Back 100

ldd /usr/bin/gedit

OR

ldd `which gedit`

Front 101

Where is Dynamic Library configuration stored?

Back 101

The dynamic loader uses two configuration files to find executables:

/etc/ld.so.conf
/etc/ld.so.cache

If you change anything in ld.so.conf, you must run ldconfig to regenerate /etc/ld.so.cache

Front 102

How would you override the default dynamic library configuration for a particular program?

Back 102

export LD_LIBRARY_PATH=/opt/extra/stuff:/opt/new/stuff

Front 103

Why would you set the variable LD_LIBRARY_PATH?

Back 103

To override the default dynamic library configuration before launching a program.

Front 104

What does the following command do?
apt-get -s install program

Back 104

It simulates the installation of a program on a Debian system.

Front 105

What command simulates the installation of a program on a Debian system?

Back 105

apt-get -s install program

OR

dpkg -i --simulate package.deb

Front 106

What is the file /etc/apt/sources.list used for?

Back 106

It stores the APT repository configuration.

Front 107

Which file stores the APT repository configuration?

Back 107

/etc/apt/sources.list

Front 108

What does the 'apt-setup' command do?

Back 108

It manages APT repositories.

[Note: This is obsolete on Ubuntu, and perhaps on Debian too! However, it may be on the exam still.]

Front 109

What do the following grep arguments do?

grep -Hr "whatever" /*

grep -hr "whatever" /*

Back 109

-H prints the file name
-h suppresses printing of the file name.

The default behaviour depends on the input that grep was searching. For example, if you tell grep to search a number of files, it will automatically print the filename beside each line matched.

Front 110

What does the 'apt-cdrom add' command do?

Back 110

It adds a CDROM to your APT repository list.

Front 111

What command adds a CDROM to your APT repository list?

Back 111

apt-cdrom add

Front 112

What does the 'apt-get update' command do?

Back 112

It retrieves a list of all available packages from each repository configured on a Debian system

Front 113

What command retrieves a list of all available packages on a Debian system?

Back 113

apt-get update

Front 114

What does the 'apt-get remove' command do?

Back 114

It removes a package from a Debian system.

Front 115

What command removes a package on a Debian system?

Back 115

apt-get remove program

or

dpkg -r package.deb

Front 116

What does the 'apt-config' command do?

Back 116

It's used to display APT configuration (Stored in /etc/apt/apt.conf or /etc/apt/apt.conf.d/) and to make config changes.

Front 117

What command can be used to display APT configuration (Stored in /etc/apt/apt.conf or /etc/apt/apt.conf.d/) or to make config changes?

Back 117

apt-config

Front 118

What does the 'dpkg --info' command do?

Back 118

It examines a Debian .deb package file.

Front 119

What command examines a Debian .deb package file?

Back 119

dpkg --info

Front 120

What does the 'dpkg --contents' command do?

Back 120

It displays the contents of a Debian .deb package file.

Front 121

What command displays the contents of a Debian .deb package file?

Back 121

dpkg --contents package.deb

Front 122

What does the 'dpkg -s' command do?

Back 122

It displays the status of a Debian .deb package.

Front 123

What command displays the status of a Debian .deb package?

Back 123

dpkg -s package.deb

Front 124

What does the 'dpkg -L' command do?

Back 124

It displays all files that were installed by a Debian .deb package.

Front 125

What command displays all files installed by a Debian .deb package?

Back 125

dpkg -L package.deb

Front 126

What does the 'dpkg -S' command do?

Back 126

It finds out which Debian package installed a particular file.

Front 127

What command finds out which Debian package owns a file?

Back 127

dpkg -S /usr/bin/program

[Hint: Search packages for owner]

Front 128

What do the following commands do?
dpkg --get-selections
dpkg --set-selections

Back 128

They are used to get or set package selections on a Debian system.

Front 129

What does the 'dpkg-reconfigure' command do?

Back 129

It reconfigures a package which has already been installed onto a Debian system.

Front 130

What command reconfigures a package which has already been installed onto a Debian system?

Back 130

dpkg-reconfigure program

Front 131

What does the 'dselect' command do?

Back 131

It is an ncurses-based program used to manage packages on Debian based systems.

Front 132

What ncurses-based program is used to manage packages on Debian based systems?

Back 132

dselect

Front 133

What does the following command do?
apt-get dselect-upgrade

Back 133

It applies package selections set through dselect.

Front 134

What command applies package selections set through dselect?

Back 134

apt-get dselect-upgrade

Front 135

What does the 'apt-cache search' command do?

Back 135

It searches the Debian repositories for a program

Front 136

What command searches the Debian repositories for a program?

Back 136

apt-cache search

Front 137

What does the 'rpm -ivh' command do?

Back 137

It installs an RPM package, giving verbose output and showing a progress bar made out of '#' characters.

Front 138

What command installs an RPM package?

Back 138

rpm -i package.rpm

Typically, this will be issued with 'v' for verbose output and 'h' to show installation progress with a 'hash' progress bar.

Front 139

What does the 'rpm -Uvh' command do?

Back 139

It upgrades an RPM package, displaying verbose output and uninstallation progress using 'hashes'

Front 140

What command upgrades an RPM package?

Back 140

rpm -Uvh package.rpm

Front 141

What does the 'rpm -e' command do?

Back 141

It uninstalls an RPM package.

Front 142

What command is used to uninstall RPM package?

Back 142

rpm -e program

Front 143

What does the 'rpm -i --force' command do?

Back 143

It forcibly installs an RPM package ignoring dependency problems or other controls.

Front 144

What command forcibly installs an RPM package, even if it has already been installed?

Back 144

rpm -i --force

Note that this will still fail to install if dependencies are not met!!

Front 145

What does the 'rpm -e --nodeps' command do?

Back 145

It forcibly removes an RPM package, ignoring dependency problems.

Front 146

What command forcibly removes an RPM package, ignoring dependency problems?

Back 146

rpm -e --nodeps

Front 147

What does the 'rpm -qi' command do?

Back 147

It queries the RPM database for a program and display information about it.

Front 148

What command queries the RPM database for a program and display information about it?

Back 148

rpm -qi program

Front 149

What does the 'rpm -qa' command do?

Back 149

It queries the RPM database and lists all installed packages.

Front 150

What command queries the RPM database and list all installed packages?

Back 150

rpm -qa

Front 151

What does the 'rpm -ql' command do?

Back 151

It list the files installed by a particular RPM package.

Front 152

What command queries display files installed by a particular RPM package?

Back 152

rpm -ql program

Front 153

What does the 'rpm -qlc' command do?

Back 153

It lists configurations files installed by an RPM package.

Front 154

What command displays configuration files installed by an RPM package?

Back 154

rpm -qlc package.rpm

Front 155

What does the 'rpm -qpi' command do?

Back 155

It Queries a Package file and shows Information about it.

Front 156

What command displays information about an RPM package?

Back 156

rpm -qpi

Front 157

What does the 'rpm -qf' command do?

Back 157

It tells you which RPM package owns a file.

Front 158

What command finds out which RPM package owns a file?

Back 158

rpm -qf /usr/bin/program

Front 159

What does the following command do:

rpm -qR program

Back 159

It lists the dependencies required by the installed "program". To list the dependencies of a package, use 'rpm -qpR package.rpm'.

Front 160

What command finds out which dependencies are required by an RPM package?

Back 160

rpm -qR package.rpm

Front 161

What does the 'rpm --checksig' command do?

Back 161

It verifies the integrity of an RPM file.

Front 162

What command verifies the integrity of an RPM file?

Back 162

rpm --checksig package.rpm

Front 163

What does the 'rpm -V' command do?

Back 163

It verifies an installed RPM. (Do not reference the package file, but the application name)

Front 164

What command verifies a program after it has been installed via RPM package?

Back 164

rpm -V program

(You don't run the command against the RPM file)

Front 165

What does the 'rpm --showrc' command do?

Back 165

It displays the RPM configuration file (rpmrc).

Front 166

What command displays the RPM configuration file (rpmrc)?

Back 166

rpm --showrc

Front 167

What is the IO address and IRQ of COM 1 (ttyS0)

Back 167

3f8, IRQ 4

Front 168

What is the IO address and IRQ of COM 2 (ttyS1)

Back 168

2f8, IRQ 3

Front 169

What is the IO address and IRQ of COM 3 (ttyS2)

Back 169

3e8, IRQ 4

Front 170

What is the IO address and IRQ of COM 4 (ttyS3)

Back 170

2e8, IRQ 3

Front 171

What is the IO address and IRQ of LP0 (LPT1)?

Back 171

378-37f, IRQ 7

Front 172

What is the IO address and IRQ of LP1 (LPT2)?

Back 172

278-27f, IRQ 5

Front 173

To set up a connection to your ISP via your modem, what settings should you configure?

Back 173

Configure the dialer, PPP settings and ppd daemon.

Front 174

Which modem speed may be too high if your computer doesn't have a 16550 UART?

Back 174

11520. You should use 56700 instead.

Front 175

What does 'isapnp' require in order to detect your sound card?

Back 175

OSS sound modules for your kernel

Front 176

What does the 'sndconfig' utility use to detect sound cards?

Back 176

isapnp

Front 177

What are the bus width and throughput of SCSI-1?

Back 177

8bit
5MB/s

Front 178

What are the bus width and throughput of 'Wide SCSI'?

Back 178

16bit
10MB/s

[Same clock speed as SCSI 1 and 2, but the wider bus enables faster bitrates]

Front 179

What are the bus width and throughput of Fast SCSI

Back 179

8bit
10MB/s

[SCSI-2, or Fast SCSI, has 2x clock speed of SCSI-1]

Front 180

What are the bus width and throughput of Fast Wide SCSI

Back 180

16bit
20MB/s

[SCSI-2, or Fast SCSI, has 2x clock speed of SCSI-1. The wider bus doubles the throughput again.]

Front 181

What are the bus width and throughput of 'Ultra SCSI'?

Back 181

8bit
20MB/s

[SCSI-3, or Ultra SCSI, has 4x clock speed of SCSI-2]

Front 182

What are the bus width and throughput of 'Ultra Wide SCSI' (aka SCSI 3)?

Back 182

16bit
40MB/s

[SCSI-3, or Ultra SCSI, has 4x clock speed of SCSI-1. The wider bus doubles the throughput again.]

Front 183

What are the bus width and throughput of 'Ultra2 SCSI'?

Back 183

8bit
40MB/s

[SCSI-3 SPI2, or Ultra2 SCSI, has 8x clock speed of SCSI-1.]

Front 184

What are the bus width and throughput of 'Wide Ultra2'?

Back 184

16bit
80MB/s

[SCSI-3 SPI2, or Ultra2 SCSI, has 8x clock speed of SCSI-1. The wider bus doubles the throughput again.]

Front 185

Describe the kernel USB drivers

Back 185

Host controller: usb-ohci.o, and usb-uhci.o, uhci.o and ehci-hcd.o

Class: hid.o, usb-storage.0, acm.o, printer.o and audio.o

Other: rio500.0, pwc.o and misc vendor-specific drivers.

Front 186

Why might you wish to put /usr on a separate partition?

Back 186

This allows you to share it read-only via NFS, so that other systems can use it. This was popular back when storage spaces was limited.

Front 187

Which command is equivalent to 'gzip -d'?

Back 187

gunzip

Front 188

Which command is equivalent to 'gunzip'?

Back 188

gzip -d

Front 189

What is the variable '$PS1' used for?

Back 189

It contains the BASH prompt.

Front 190

What is the BASH prompt variable?

Back 190

$PS1

Front 191

When setting the prompt variable in BASH, what represents the current user?

Back 191

\u

Front 192

When setting the prompt variable in BASH, what represents the hostname?

Back 192

\h

Here's the lot...
* \a : an ASCII bell character (07)
* \d : the date in "Weekday Month Date" format (e.g., "Tue May 26")
* \D{format} : the format is passed to strftime(3) and the result is inserted into the prompt string; an empty format results in a locale-specific time representation. The braces are required
* \e : an ASCII escape character (033)
* \h : the hostname up to the first '.'
* \H : the hostname
* \j : the number of jobs currently managed by the shell
* \l : the basename of the shell’s terminal device name
* \n : newline
* \r : carriage return
* \s : the name of the shell, the basename of $0 (the portion following the final slash)
* \t : the current time in 24-hour HH:MM:SS format
* \T : the current time in 12-hour HH:MM:SS format
* \@ : the current time in 12-hour am/pm format
* \A : the current time in 24-hour HH:MM format
* \u : the username of the current user
* \v : the version of bash (e.g., 2.00)
* \V : the rel

Front 193

When setting the prompt variable in BASH, what represents the basename of the current working directory?

Back 193

\W

Front 194

How would you display the 2nd column of a CSV file using the 'cut' command?

Back 194

cut -d, -f2 file.csv

Front 195

What does the 'expand' command do?
expand -i /var/log/file

Back 195

It converts the initial tabs on each line into into spaces.

Front 196

What does the 'join' command do?

Back 196

The join command is like a database join. If two text files contain one identical columns (eg, column 1 in both files is a sequence of numbers), then both files can be joined at this field with the following command:

join -j 1 file1.txt file2.txt

Front 197

What does the 'nl' command do?

Back 197

This command numbers each line in a file

Front 198

What command numbers each line in a file?

Back 198

nl

NOTE: You can also use awk:

awk '{ print NR" "$0 }'

Front 199

What does the 'od' command do?

Back 199

"'Octal dump' is mostly used to examine the byte code of binary files

Front 200

What command can be used to examine the byte code of a binary file or input stream?

Back 200

od (Octal Dump)

Front 201

What does the 'paste' command do?

Back 201

This command takes files as arguments, and pastes corresponding lines from each file in columns, specifying a delimeter.

For example, if file1.txt contains ascending numbers and file2.txt contains ascending letters, the output of 'paste -d, file1.txt file2.txt' would be:

1,A
2,B
3,C
4,D

...etc

Front 202

What does the 'sort' command do?

Back 202

It sorts a file or stdin.

sort -n - numerical sort -f - ignore case
sort -r - reverse sort order
sort -k 5,10 - sort lines 5 to 10

[Note that the -t argument may be necessary to tell 'sort' what delimiter to use between fields]

Front 203

split -2 /var/log/file splitfiles_

Back 203

It splits the file /var/log/file every 2 lines and outputs to multiple files beginning 'splitfiles_'

Front 204

What command splits a file every 2 lines into multiple files beginning 'splitfiles_'

Back 204

split -2 /var/log/file splitfile_

Front 205

Which command should you use to translate characters in a file from lower case to upper case?

Back 205

There are two ways:

cat file | tr a-z A-Z
cat file | tr '[:lower:]' '[:upper:]'

Front 206

The file /tmp/file contains the following:
1 2 3 4
56 7 8 9 10

How would you use the 'tr' command to remove all repeated spaces in the file?

Back 206

cat file | tr -s '[:blank:]'

Front 207

What does this command do:
cat file | tr -s '[:blank:]'

Back 207

It reads a file and ignores all duplicate blank lines.

[-s is --squeeze-repeats]

Front 208

What does the 'unexpand' command do?

Back 208

Unexpand replaces spaces with tabs (seems to be the opposite of what it should do!)

Front 209

What command replaces spaces with tabs (which are 8 spaces by default)?

Back 209

unexpand

Front 210

What does the 'uniq -u' command do?

Back 210

Shows unique lines in a file or standard input

Front 211

What command shows unique lines in a file or standard input?

Back 211

uniq -u

NOTE: The default action of uniq is to remove duplicates.

Front 212

What does the 'uniq -d' command do?

Back 212

Shows non-unique lines in a file or standard input

Front 213

What command shows non-unique lines in a file or standard input?

Back 213

uniq -d

Front 214

What does the 'wc' command do?

Back 214

It counts the words in a file.

Front 215

What command counts the words in a file

Back 215

wc file

Front 216

What would the following command do?
find / -type f | xargs -n 1 grep -H linux

Back 216

First, it finds all files in the root directory.

These file names are piped to xargs, which takes a maximum of one argument per line to pass to grep.

grep -H searches each file for the word 'linux', which uses "-H" to display the name of each file it finds it in.

xargs syntax:
xargs [options] [command] [arguments]

Typically, arguments are piped from standard input.

Front 217

How would you go about configuring an ISA pnp card?

Back 217

isapnp requires a configuration file to be created with pnpdump.

pnpdump >/etc/isapnp.conf
isapnp /etc/isapnp.conf

Front 218

What command shows all environment variables that are currently set?

Back 218

env

Front 219

What does the 'env' command do?

Back 219

It displays all environment variables that are currently set

Front 220

What's the difference between info and man?

Back 220

Man pages are flat. Info uses hypertext to help organise documents.

Front 221

What command reformats paragraphs within a text file?

Back 221

fmt

Front 222

What does the 'fmt' command do?

Back 222

It reformats paragraphs within a text file

Front 223

What is the difference between grep and egrep?

Back 223

grep uses basic regular expressions by default, whereas egrep uses extended regular expressions by default.

Front 224

What does this command do?

tail -f /var/log/messages

Back 224

It displays the last few lines of /var/log/messages, and continues to monitor the file, updating the screen every time a new line is added.

Front 225

What command displays the last few lines of a file and continues to monitor it, displaying new lines as they're added?

Back 225

tail -f file

Front 226

What does the 'renice' command do?

Back 226

Renice alters the priority or running processes.

20 - idle
0 - realtime

Front 227

What does the 'nice' command do?

Back 227

Nice allows you to run a command while specifying its priority. For example:

nice 0 amarok

This would launch amarok with 'realtime' priority.

Front 228

What does the 'uptime' command do?

Back 228

It displays the amount of time the system has been running, and also three load averages: the past minute, the past 5 minutes and the past 15 minutes.

Front 229

What does the 'uname' command do?

Back 229

It displays:
Hardware platform
Processor type
Kernel name, version
Hostname
OS name

Front 230

What command kills a process by name?

Back 230

killall [processname]

OR

pkill [processname or part thereof]

Front 231

Traditionally, the linux kernel must reside below which cylinder?

Back 231

1024th cylinder. However, newer versions of GRUB and LILO will work from any part of the disk if the BIOS supports it.

Front 232

What are the major fdisk commands?

Back 232

d delete a partition
l list known partition types
n add a new partition
p print the partition table
v verify the partition table
q quit without waving
w write the table and exit

Front 233

How does linux burn optical media?

Back 233

It uses mkisofs to create an ISO-9660 filesystem, and cdrecord to burn it to the media.

Front 234

Which command is used to create a filesystem?

Back 234

mkfs

Front 235

On which partitions type(s) can the Linux kernel reside?

Back 235

It can reside on primary or logical partitions. Extended partitions are placeholders for more logical partitions.

Front 236

What is the default install location for software installed from source?

Back 236

/usr/local/

Front 237

How can you prevent filesystem checks after a power failure?

Back 237

Use a journaled filesystem like JFS, XFS, EXT3, EXT4 or ReiserFS.

Front 238

Where should you install GRUB or LILO if you want to be able to restore it using DOS fdisk after installing Windows?

Back 238

You must install it to the partition's boot sector, not to the MBR.

Front 239

What is the function of the 'sticky bit'

Back 239

The sticky bit is set on directories to ensure that only the a file's owner may delete it.

Front 240

What does the 'umask' command do?

Back 240

It shows the numeric value being subtracted from the default permissions of newly created files and folders. For example:

umask = 0022

This means the default permission is x755:

-rwxr-xr-x

Front 241

The following python command prints text to screen. What will it look like?

print ("I", "have", "lice")

Back 241

I have lice

By default, python prints each value using a space as a separator. You can change this behaviour by specifying end=""

print (end="_" "Here", "I", "am")

Here_I_am

Front 242

What does the 'edquota' command do?

Back 242

It edits disk quota information.

Front 243

What command edits disk quota information?

Back 243

edquota

Front 244

What is a 'hard link'

Back 244

A hard link is a filename that points to the inode of another file. Think about data recover, and the purpose of the file table; if you have two file table entries pointing to a single inode, then deleting one has no effect on the other. Changing the file content does, of course.
Here is an example of what you would see after creating a hard link and a soft link:

HOST1:# touch original_file
HOST1:# ln original_file hardlink
HOST1:# ln -s softlink

Now, displaying the inode with the ls command (short date, no user or group):

HOST1:# ls -lAgG --time-style iso
total 0
-rw-r--r-- 2 0 11-29 16:08 hardlink
-rw-r--r-- 2 0 11-29 16:08 original_file
lrwxrwxrwx 1 13 11-29 16:11 softlink -> original_file

Front 245

What is a 'symbolic link'?

Back 245

A symbolic link points to another file by its entry in the file table, rather than to the inode on the disk. If you remove the original file, its entry in the file table is removed (though the inode is not necessarily wiped) and the symbolic link no longer works.

Front 246

What modes does vi have?

Back 246

Command mode
Insert Mode
Ex Mode (used to enter external commands)

Front 247

Which file directs the boot process after the kernel has loaded?

Back 247

/etc/inittab OR files in /etc/event.d/

Front 248

What does the 'dmesg' command do?

Back 248

It allows you to examine the 'kernel ring buffer' after the kernel has loaded. Essentially, this is a log of kernel events recorded during boot.

Front 249

What does the 'runlevel' command do?

Back 249

It shows the computer's current runlevel. It can also be used with the --set option to set the runlevel.

Front 250

What command can show or change the current runlevel?

Back 250

runlevel

Front 251

What option must be set in the /etc/ssh/sshd_config file to enable X tunneling?

Back 251

X11Forwarding yes

Front 252

What program does Linux use to convert PostScript into non-PostScript formats?

Back 252

Ghostscript

Front 253

What is the role of a filter in a Linux printing system?

Back 253

A filter identifies the file type and passed it through the appropriate programs to convert it into something the printer understands.

Front 254

What command displays information about the print queue?

Back 254

lpq

Front 255

What does the 'lpq' command do?

Back 255

It displays information about print queues.

Front 256

What does the 'mpage' utility do?

Back 256

It prints several pages onto one PostScript page to save on paper.

Front 257

What types of network printer can CUPS print to?

Back 257

IPP, LPD and SMB/CIFS

Front 258

What does the 'lpr' command do?

Back 258

It submits a print job.

Front 259

What command is used to submit a print job?

Back 259

lpr

Front 260

What are the main XDMCP servers in Linux?

Back 260

XDM, KDM and GDM

Front 261

What does the 'lprm' command do?

Back 261

It removes a print job from a print queue.

Front 262

What command removes a print job from a print queue?

Back 262

lprm

Front 263

What option do you pass to the lpr command to specify a printer

Back 263

lpr -Plexmark

Front 264

What factors does X use to compute the refresh rate?

Back 264

The monitor's maximum horizontal and vertical refresh rates and the resolution.

Front 265

Why would you set the LC_ALL variable?

Back 265

To change the locale for a single program.

Front 266

How would you override the locale for a single program?

Back 266

export LC_ALL

Front 267

What does the 'chage' command do?

Back 267

It changes a user's password expiration information.

Front 268

What command changes a user's password expirey information?

Back 268

chage

Front 269

What command locates all files belonging to a particular user?

Back 269

find / -uid 502

Front 270

Which file records group memberships?

Back 270

/etc/group

Front 271

What command lets you create a user cron job?

Back 271

crontab

Front 272

What does the 'crontab' command do?

Back 272

It allows you to maintain cron jobs for individual users.

Front 273

What does the command 'userdel -r raff' do?

Back 273

It deletes the user 'raff' and removes the user's home directory.

Front 274

What command removes a user and deletes their home drive?

Back 274

userdel -r username

Front 275

How would you prevent a user from using crontab?

Back 275

Add the user to /etc/cron.deny

Front 276

What does klogd do?

Back 276

It intercepts and logs kernel messages from the overall system log daemon.

Front 277

What command(s) can identify slow or unreliable routers between you and another system?

Back 277

traceroute and tracepath

Front 278

Which server runs on port 53?

Back 278

DNS

Front 279

Which port does DNS use?

Back 279

53

Front 280

What is the difference between UDP and TCP?

Back 280

UDP is connectionless, and it has no packet-level error checking. This reduced overhead makes it much faster than TCP. It is useful for improving the performance of online gaming, video streaming etc, where 100% of the transmitted data may not necessarily be required.

Front 281

Why is telnet generally avoided?

Back 281

Telnet isn't encrypted, and is therefore insecure. SSH is recommended for remote shell access.

Front 282

Which file would you edit to have postmaster email delivered to you?

Back 282

Depending on the distribution, it may be either of these:
/etc/mail/aliases
/etc/aliases

Front 283

Where would you set global BASH options for all users?

Back 283

Any of these:
/etc/bashrc
/etc/bash.bashrc
/etc/profile

Front 284

How can you check if an SMTP email has been sent?

Back 284

Type mailq to view the message queue.

Front 285

What does the 'newaliases' command do?

Back 285

It forces the mail server to read the /etc/aliases or /etc/mail/aliases file after it has been changed.

Front 286

After you make a change to the /etc/aliases or /etc/mail/aliases file what command should you run for the changes to take effect?

Back 286

newaliases

Front 287

What is the difference between .profile and .bashrc?

Back 287

.profile is only executed in login shells, whereas .bashrc files launch for any bash shell.

Front 288

What does /etc/nologin do?

Back 288

It prevents non-root users from logging into shells. It can contain a message the will be shown to users if they try to connect.

Front 289

What is inetd?

Back 289

It's a "superserver" that launches other servers on demand. It uses the /etc/inetd.conf for its configuration.

inetd differs from xinetd in that it uses TCP Wrappers, whereas xinetd is much more powerful and configurable, with its own built-in access controls, limits and logging features.

Front 290

What advantages does xinetd have over inetd?

Back 290

inetd must use TCP wrappers (i.e. /etc/hosts.allowed and /etc/hosts.denied) for security, but xinetd has security features built in.

Front 291

What utility uses /etc/hosts.allow and /etc/hosts.deny?

Back 291

TCP Wrappers use these files for access control. (The main user of TCP Wrappers is inetd, thought some other programs use it). To find out if a program supports TCP Wrappers, use this command:

ldd /usr/bin/program | grep libwrap

Front 292

What utility manages ssh logins, enabling you to use a single passphrase instead of typing a password for each connection?

Back 292

ssh-agent

Front 293

What file holds ssh information about all known hosts for all users

Back 293

/etc/ssh/ssh_known_hosts

Front 294

Monitoring progress: If you wished to draw a rotating line on the screen during a process, how would you echo to the same character space onscreen?

Back 294

echo \b\c

In order to use the backslash characters on echo in bash, you have to use the '-e' option. This is not the default on many distros!

Front 295

System account information such as user ID and group ID is stored in which file?

Back 295

/etc/passwd

Front 296

What does the 'tee' command do?

Back 296

It takes standard input, and redirects output to the screen and to a file.

Example: If you needed to echo a new line to a file owned by root, the following command would fail:

sudo echo "Newline" > /etc/newfile

While 'echo' is executed with root privileges, the redirect happens outside of 'sudo'. The correct command is:

echo "Newline" | sudo tee /etc/newfile

Front 297

What does the 'unset' command do?

Back 297

It is used to remove a shell variable; it is the opposite of set.

Front 298

What would this command do?
mkdir /tmp/bar || echo "oops"

Back 298

It would try to create the /tmp/bar folder. If it fails, it will echo "oops". || is an 'OR' logical operator.

Front 299

What is the default signal for the kill command?

Back 299

SIGTERM

Though SIGTERM is the default, it can be specified by using either of these commands:

kill -TERM process
kill -15 process

This type of kill signal can be blocked if the process cannot be cleanly killed.

Front 300

What is SIGTERM?

Back 300

Sigterm is the default 'signal' for the kill command. It sends a 'kill' command to the process. The process itself then tries to terminate. However, this does not always work, as the process may block the request or fail to terminate.

Though SIGTERM is the default, it can be specified by using either of these commands:

kill -TERM process
kill -15 process

Front 301

What is SIGKILL?

Back 301

SIGKILL is a signal for the 'kill' command. It does not send a 'kill' command to the process, but to the kernel. As such, it cannot be blocked.

SIGKILL can be specified by using either of these commands:

kill -KILL process
kill -9 process

Front 302

What does the 'pkill' command do?

Back 302

The 'pkill' command works in exactly the same way as the 'kill' command, except that it can be passed process names instead of PID numbers. For example, the following commands would forcibly kill the firefox process:

pkill -9 firefox
pkill -KILL firefox

Front 303

Which redirector is used to direct the standard error to a file?

Back 303

2>

Front 304

How would you alter the priority of a running process?

Back 304

You could use the 'renice' or 'top' commands.

Front 305

What commands can be used to create an ext2 filesystem?

Back 305

mke2fs
mkfs.ext2

(mkfs.ext2 is a link to mke2fs)

Front 306

What command would you use to check an ext2 or ext3 filesystem?

Back 306

You could use the following commands:

e2fsck
fsck.ext2
fsck.ext3

Front 307

What command would you use to check an ext4 filesystem?

Back 307

fsck.ext4

Front 308

What's the bash history file called?

Back 308

~/.bash_history

Front 309

What's the default BASH history size?

Back 309

500 lines

Front 310

What is the name of the variable that controls BASH history size?

Back 310

$HISTSIZE

Front 311

What does "!!" do in BASH?

Back 311

It executes the previous command

Front 312

What would "!ssh" do in BASH?

Back 312

It would execute the last command that started with 'ssh'.

Front 313

What would "!123" do in BASH?

Back 313

It would execute the 123rd command in the BASH history.

Front 314

What does "!$" represent in BASH?

Back 314

It represents the last argument of the previous command.

Front 315

What would "!23:p" do in BASH?

Back 315

It would print the 23rd command in the BASH history

Front 316

What to the following BASH history modifiers do?

!$:h
!$:t
!$:r
!$:e
!!:p
!!:s/balls/walls/g

Back 316

!$:h - 'head', shows the path but not the filename
!$:t - 'tail', shows the filename but not the path
!$:r - shows the full path, but removes the file extension
!$:e - 'end'; just shows the file extension
!!:p - prints the command but doesn't execute it.
!!:s/john/harry - repeats the command, replacing the first instance of "john" with "harry"
!!:s/hda/sda/g - repeats the command, globally replacing "hda" with "sda"

Front 317

What would the following BASH history shortcut do?

!!:gs/hda/sda

Back 317

It would repeat the previous command, replacing all instances of 'hda' with 'sda'.

Front 318

What would the following BASH history command do?

!!:s/one/two

Back 318

It would repeat the previous command, replacing the first instance of 'one' with 'two'. This is equivalent to:

^one^two

Front 319

What would the following BASH history command do?

^tzr^tar

Back 319

It would repeat the previous command, replacing the first instance of 'tzr' with 'tar'. This is equivalent to:

!!:s/tzr/tar

Front 320

Which CTRL key is used to go to the start of the BASH command line?

Back 320

CTRL + a

Front 321

Which CTRL key is used to go to the end of a BASH command line?

Back 321

CTRL + e

Front 322

Which CTRL key is used to clear the BASH screen?

Back 322

CTRL + l

Front 323

Which keystrokes can be used in BASH when cursor keys do not work?

Back 323

Readline
CTRL + p = Previous (up)
CTRL + n = Next (down)
CTRL + b = Back one character
ALT + b = Back one word
CTRL + f = Forward one character
ALT + f = Forward one word
CTRL + a = Home
CTRL + e = End
CTRL + w = Delete previous word
ALT + w = Delete next word


For a complete 'readline' cheat sheet:
http://www.bigsmoke.us/readline/shortcuts

Front 324

Which CTRL keys are used to search the BASH history?

Back 324

CTRL + r = Reverse search

[Once you have found the command, ENTER to execute, CTRL + j to edit it.]

Front 325

Describe the two ways in which you can substitute a command for a variable or value in a BASH command.

Back 325

`command`
$(command)

Examples:
profile =`ls .mozilla/firefox/ | grep default`
rcsize = $(wc -l ~/.bashrc)

Front 326

How would you find and delete all .zip files in a folder and its subfolders?

Back 326

There are several methods:

The first method you could use is the built-in 'exec' option that the 'find' command provides:

find /folder -iname "*.zip" -exec rm "{}" \;

The second option is to use the 'xargs' command along with 'find':

find /folder -iname "*.zip" | xargs rm *

The third option is only possible with newer versions of find:

find /folder -iname "*.zip" -delete

Front 327

What regular expression would you used with grep to find all lines in a file beginning with "http" or "ftp"?

Back 327

grep -E "^(ht|f)tp" file

OR

egrep "^(ht|f)tp" file

^ represents the start of the line

Braces () let you search for strings using the OR logical operators, represented by a | pipe.

"egrep" and "grep -E" argument use extended regular expression.

Note: -e just allows you to specify multiple 'regular' regular expressions.

Front 328

How can your script tell if it's in an interactive BASH shell?

Back 328

The variable "$-" will contain the letter i.

Front 329

How would you redirect command output to several different files?

Back 329

In your BASH script, you can direct output to named file descriptors:

echo option $OPTSTR >&5

From the command line, you can tell your script which file this descriptor should write to like this:

$ command 5> output

Front 330

Explain the difference between these commands:

$ somecmd >my.file 2>&1
$ somecmd 2>&1 >my.file

Back 330

This may appear counter-intuitive, so pay attention!

In the first case, standard out is redirected to a file (my.file), and then standard error is redirected to "the place that standard out is directed", which means that all output appears in my.file.

However, in the second command, standard error is redirected to standard out (which at that point is connected to the screen), after which standard out is redirected to my.file. Thus, standard output appears in my.file while standard error appears onscreen.

Front 331

What does this command do:
$ set -o noclobber

Back 331

It unsets the noclobber option. This tells BASH to be more careful about overwriting files that already exist.

Note: To undo, use this command:
$ set +o noclobber

You can override noclobber by redirecting like this:

echo "whatever" >| /tmp/file

Front 332

How would you achieve the same result as this without the cat command:

cat /tmp/file | wc

Back 332

wc < /tmp/file

Note: cat is overused, but can improve the readability of 'long' commands by placing the cat /tmp/filename at the beginning.

Front 333

What is a 'here-document'?

Back 333

If you wish to place data inside a simple script, you can use what is called a 'here-document'. Example script called "ext":

# here is a "here" document
#
grep $1 <<EOF
mike x.123
joe x.234
sue x.555
pete x.818
sara x.822
bill x.919
EOF

Command: ext joe
Result: joe x.234

Front 334

How can you ask for BASH user input?

Back 334

read -p "Enter some text" VARIABLE

Note: If you want to prompt, but hide input (as with a password prompt) use:

read -s -p "Enter password" PASSWORD

Front 335

What is BASH script exit status?

Back 335

$? represents the exit variable. This can be set to a particular value on exit, depending on whether or not the command was successful.

For example:

if [ $value -le 10 ]; then
exit 5
fi

By default, a zero value means 'success', and a non-zero value means 'failure'.

Front 336

How would you show the last two lines of a text file?

Back 336

tail -2 textfile

While this works, it's less confusing to use:

tail -n 2 textfile

Front 337

How would you show a text file, but skip the first 4 lines?

Back 337

tail -n +4 textfile

Note: This has changed! It is documented in many places like this:

tail +4 filename


...but this will attempt to 'tail' the text file, and also a file named "+4".

Note also that the syntax of tail to show the last 4 lines should also be formatted in this way for simplicity:

tail -n 4 filename

Front 338

How can you run several commands at once?

Back 338

Separate the commands with ampersands:

/usr/bin/runme &
/etc/init.d/restart &
/control/scripts/update

Note: If you want to run commands consecutively, use semi-colons.

Front 339

How can you run several commands consecutively?

Back 339

If you only want to run the next command if the previous one succeeds:

./configure && make && make install

If you want to run all commands regardless of whether or not the previous one fails:

touch ~dir ; cd ~dir ; cp file ~

Front 340

How can you use the output of a command, and redirect it to a file simultaneously?

Back 340

Use the 'tee' command to T-joint the output:

find ~ -type f | tee list.txt | grep -i ".doc"

Front 341

You ping a host and redirect output to a file. However, the error message still appears onscreen. How do you overcome this? Why does it happen?

Back 341

Explanation: Ping is behaving properly! Every Unix process typically has three open file descriptors:
0> STDIN
1> STDOUT (shorthand is > )
2> STDERROR

Many programs stick to this standard, so if you wish to capture STDOUT and STDERR to a single file, you must specify this:

ping hostname > logfile 2> logfile

OR:
ping $host > logfile 2>&1

[In the alternative, the order of the redirects is important!]

Front 342

How would you use the output of a command inside another command?

Back 342

BASH has a command substitution feature that can be called by using back ticks or $().

Example:
rm `ls | grep bak`
rm $(ls | grep bak)

The $() method is recommended.

Front 343

You have written a script that generates screen output. You would like to enable this script to direct its output to multiple files. How would you accomplish this?

Back 343

Inside the script, you should echo output to numbered file descriptors:

echo $VALUE >&4
echo $ERROR >&5

When the script is executed, these file descriptors can be used like this:

runscript 4> values 5> errors

Front 344

How would you ping a host, directing output and errors to a file, while also viewing them onscreen?

Back 344

ping host 2>&1 | tee logfile

Front 345

How would you save STDERR and STDOUT to separate output files, while displaying STDERR onscreen?

Back 345

This is a trick question. If you wished to save both to separate files and show STDOUT onscreen, it would be easy direct STDERR to a file, and pipe into tee to split the STDOUT onto screen and to a file. However, there is no way to put STDERR through a pipe! You must swap STDERR and STDOUT before piping into tee. This can be achieved through an intermediate file descriptor:

command 3>&1 1>std.out 2>&3 | tee std.err

Create file descriptor 3 pointing at STDOUT. This allows it out through the pipe.

Direct standard out into a file.

Direct standard error into file descriptor 3 (buffered).

Front 346

What does the 'free' command do?

Back 346

It displays the amount of free and used memory in the system.

Front 347

What command displays free and used memory in the system?

Back 347

free

Front 348

What does the 'nohup' command do?

Back 348

It is used to run a command that is immune to the HUP (hangup) signal. This means that the command will continue to run after the user logs out. Output doesn't go to tty, but to a file called nohup.out.

Front 349

When a command is running, what happens when you press CTRL + z?

Back 349

The command is paused and sent to the background as a 'job' so you can have control of the terminal.

You can unpause a background job with the command 'bg'.

You can bring a background job to the foreground using the command 'fg'.

You can list jobs with the 'jobs' command.

Front 350

What does the 'jobs' command do?

Back 350

It is used to display a list of jobs that have been pushed into the background. (Look up BASH job control)

Front 351

What does the 'bg' command do?

Back 351

When you pause a BASH job and push it into the background with CTRL + z, the bg command leaves it in the background but resumes the job. This gives you interactive control over the shell (though you will get STDOUT from the background command on the screen!). To bring the job back to the foreground, use 'fg'.

Front 352

What does the 'updatedb' command do?

Back 352

It updates (or creates) a database of files for the 'locate' command. [This is usually executed by cron on a daily basis.] Locate is much faster than find because it doesn't have to search the file table, but looks inside a database.

Front 353

What does the 'locate' command do?

Back 353

It is used to find files. It works much quicker than the 'find' command because it queries the 'mlocate' database rather than the filesystem.

Front 354

What does the 'which' command do?

Back 354

It is used specifically for locating commands.

Front 355

What does the 'whereis' command do?

Back 355

It is used to find binary, source and man page of a command.

Front 356

What port number does IMAP use?

Back 356

143

Front 357

What service uses port 143?

Back 357

IMAP

Front 358

How would you configure visudo to edit the /etc/sudoers file in an editor other than vi?

Back 358

export EDITOR=/usr/bin/gedit

Front 359

What would you add to the /etc/sudoers file to give the group "admins" the ability to run any command with sudo without needing a password?

Back 359

%admins ALL=(ALL) NOPASSWD: ALL

The general format of sudoers is:
user host=(user you can run as) command

Front 360

How many command line arguments to useradd can you remember?

Back 360

-c comment
-d home directory
-D Don't create, just use these as default values
-g Set the primary group
-G Add the user to a comma-delimited list of groups
-m Create a home directory using /etc/skel
-M Do not create a home directory
-p Password
-s Shell
-u

Front 361

How would you restrict user logins based on time, date etc?

Back 361

You could use enable the pam_limits module and configure the /etc/security/limits.conf file:

* soft core 0
* hard rss 10000
@student hard nproc 20
@faculty soft nproc 20
@faculty hard nproc 50
ftp hard nproc 0
@student - maxlogins

Front 362

How would you sniff packets on the eth0 interface, ignoring SSH packets?

Back 362

tcpdump -i eth0 not port 22

Front 363

How would you install an RPM to a different Linux installation on another partition?

Back 363

rpm -i --root /mnt/other

Front 364

How would you extract files from an rpm package?

Back 364

rpm2cpio package.rpm | cpio -ivd

The cpio command line arguments are:
-i extract
-v verbose
-d create directories

NOTE: To view the files, use "cpio -vt". This allows you to specify individual files to extract, if you don't want all of them.

Front 365

How would you extract files from a deb package?

Back 365

You can use dpkg to extract files:

dpkg -X package.deb

Also, since debian packages are 'ar' archives that contain three files, you can use this command:

$ ar -vx package.deb
x - debian-binary
x - control.tar.gz
x - data.tar.gz

The files can be extracted from the data.tar.gz using this command:

tar -xvzf data.tar.gz

Front 366

How would you remove a Debian package, including configuration files?

Back 366

dpkg -P package

OR

dpkg --purge package

Front 367

How do you find out which package owns a file on a Debian system?

Back 367

dpkg -S /opt/filename

OR

dpkg --search /opt/filename

Front 368

How do you show information about a package installed on a Debian system?

Back 368

dpkg -p package

OR

dpkg --print-avail package

Note: This information can be useful when creating your own packages with checkinstall.

Front 369

How do you list the files in a Debian package?

Back 369

The following command list files owned by an installed package:

dpkg -L package.deb

OR

dpkg --listfiles package.deb

However, the following command shows the contents of a package file (i.e. not installed):

dpkg -c package.deb

Front 370

How would you list unmet dependencies of a package on a Debian system?

Back 370

apt-cache unmet package_name

Front 371

How would you capture 5 packets from the source 192.168.2.105 on interface "eth0", ignoring port 22?

Back 371

tcpdump -i eth0 -c 5 src 192.168.2.105 and not port 22

Front 372

What does this "tcpdump -e" do?

Back 372

It displays source and destination MAC address and the ethertype.

Front 373

How would you capture verbose packets to the file /tmp/tcpdump.cap, originating from the network 10.30.123.0, going to the destination address 10.30.122.50.

Back 373

tcpdump -VV -w /tmp/tcpdump.cap src net 10.30.123.0 and dst host 10.30.122.50

Front 374

How you you show all of the processes that are listening on a particular port?

Back 374

netstat -l -p --numeric-ports

By default, netstat shows open sockets.
-l shows sockets that are being listened to
-p shows process IDs

NOTE: the "-n" option shows hosts, ports and users numerically. Each one can be specified 'longhand' without affecting the others.

OR

lsof -iTCP -sTCP:LISTEN

lsof lists open files, but this includes pseudo files. (In *nix, everything is a file!)

-i lists network "files"
-iTCP particularly lists TCP connections
-sTCP:LISTEN only shows TCP connections that are listening.

Front 375

What are the six types of information that netstat can show? What command line arguments are used to show them?

Back 375

The type of information shown by netstat is controlled by the first argument:

(none) Open sockets
-r Kernel routing tables
-g Multicast group memberships
-i Network interfaces
-M Masquerade connections
-s Statistics for each protocol

Front 376

How would you direct the microphone input to the speakers on your other PC?

Back 376

dd if=/dev/dsp | ssh username@host dd of=/dev/dsp

You could probably use netcat either.

Front 377

How would you create a 250MB RAM disk at /mnt/ramdisk

Back 377

mount -t tmpfs -o size=250m tmpfs /mnt/ramdisk

Front 378

How would you show which programs are listening on which tcp ports?

Back 378

netstat -tlnp

-t causes netstat to only list information about TCP sockets.
-l causes netstat to only list information about listening sockets.
-n causes netstat not to do reverse lookups on the IPs.
-p causes netstat to print the PID and name of the program to which the socket belongs (requires root).

Front 379

How do you find out who is using a file?

Back 379

lsof /pathto/file

Front 380

How do you find out which files are opened by a particular user?

Back 380

lsof -u user

Front 381

How do you show open files used by bash?

Back 381

lsof -c bash

Front 382

How do you show open files used by bash as the root user?

Back 382

lsof -a -c bash -u root

The -a option works like "and", combining the other options.

Front 383

How do you show open files used by the process ID 2123?

Back 383

lsof -p 2123

Front 384

How would you list all open network connections?

Back 384

lsof -i

OR

netstat

Front 385

How would you show all TCP connections?

Back 385

lsof -i tcp

OR

netstat -at

Front 386

How would you show all TCP network connections used by the user "raff"?

Back 386

lsof -a -u raff -i tcp

Front 387

What does the lsof option "-t" do?

Back 387

It forces lsof to produce terse output with process identifiers only. This is useful when you want to pass the results to 'kill'. For example, this command would kill all processes that have UDP connections open:

kill -9 `lsof -t -i udp`

Front 388

How would you use netcat to copy a file from one computer to another?

Back 388

# On computer A with IP 192.168.1.10
$ cat file | nc -l -p 6666

# On computer B
$ nc 192.168.1.10 6666 > file

Front 389

How would you remotely access BASH without using rsh, ssh or telnet?

Back 389

#On a computer with IP 10.30.1.2
nc -l -p 12345 -e /bin/bash

#To connect to the 'BASH server', execute this command:

nc 10.30.1.2 12345

Front 390

What would this awk command do?

awk 'NF { print $0 "\n" }' /filname

Back 390

If the first argument in awk has a non-zero value, awk will execute the remainder of the command. If it is zero, it will not.

NF specifies the number of fields in a line. If the line is:

Good morning sunshine

...then the value of NF is 3. However, if the line is blank, the number will be zero, and awk will not proceed.

This command will remove all duplicate empty lines in the file.

Front 391

What would this awk command do?

awk 'BEGIN { ORS="\n\n" }; 1' /filename

Back 391

BEGIN has special significance in awk. It is only executed once, before awk processes any lines. In this case, it sets the "Output Record Separator" to two new lines.

The next command is "1". Simply put, "1" is always true, therefore awk will print each line.

This command prints all lines of a file on a single line. The output record separator is normally a new line, but we set it to be a space.

Front 392

What would this awk command do?

awk '{ print FNR "\t" $0 }' /filename

Back 392

FNR is the "File Line Number". This command will print each line number, a tab, and then the line, like the "nl" command.

Front 393

What would this awk command do?

awk '{ print NR "\t" $0 }'

Back 393

NR is "line number", which differs from FNR in that it doesn't get reset if awk processes multiple files.

This command is useful if you wishe to process multiple files and number each line. Again, this is like "cat file1 file2 file3 | nl", but it's more flexible (because it's awk!).

Front 394

What would this awk command do?

awk 'NF { $0=++a " :" $0 }; { print }' /filename

Back 394

NF is the number of fields in the line. If this is zero, the proceeding command will not be executed.

Variables come into existence automatically in awk, so "++a" will create and/or automatically increment "a".

So the first command will convert $0 into 'a :$0' provided that the line isn't blank.

The next command simply prints each line.

This command numbers every non-blank line.

Front 395

What would this awk command do?

awk '{ total = total + NF }; END { print total+0 }'

Back 395

NF is the number of fields in a line.

Variables come into existence automatically in awk, so "total" gets incremented by the number of words in each line.

END has a special significance in awk. It is only execute once, after awk has processed all lines.

This command works like "wc".

Front 396

What would this awk command do?

awk '{ print $NF }'

Back 396

NF is the number of fields in a line.

This command prints the last field from each line.

Front 397

What would this awk command do?

awk 'NF > 4'

Back 397

Every awk program contains "pattern {action}" statements. If a pattern is missing, it is assumed to be "1", which will execute the action. If the action is missing, it is assumed to be "{ print }".

NF is the number of fields in a line.

This awk command is the same as:

awk 'NF > 4 {print}'

It will print each line that has more than four fields.

Front 398

What would this awk command do?

awk '$NF > 4'

Back 398

Every awk program contains a "pattern {action}" statement. IF a pattern is missing, it is assumed to be "1", which will execute the action. If the action is missing, it is assumed to be "{print}"

NF is the number of fields in a line.

This awk command is the same as:

awk '$NF > 4 {print}'

It will print each line where the last field is a number larger than 4.

Front 399

ldapsearch produces the following:

DN: cn=winxp1,dc=domain,ou=dept,o=com
update=21
user=paddy

DN: cn=winxp2,dc=domain,ou=dept,o=com
update=22
user=john

DN: cn=winxp3,dc=domain,ou=dept,o=com
update=15
user=philip

Problem: You wish to use awk to display the user and update on a single lines like this:

user: paddy,update: 21
user: john,update: 22
user: philip,update: 15

Back 399

NOTE: There are several ways, one that uses 'getline'; we will use a better method

awk ' BEGIN {RS="\n\n";FS="\n";OFS=","};{print $1,$2}'

In the BEGIN statement awk is told that:
- each RS (record separator) is a blank line.
- each FS (field separator) is a new line.
- The OFS (output field separator) is a comma.


With the new values, awk reads each 'record' as a series of new lines until it hits a blank one. Out of each record, it prints values $2 and $3, separated by commas.

Front 400

What sed command would you used to delete all lines containing "Arse"?

Back 400

sed '/Arse/d'

OR

sed '/Arse/!p;d'

Front 401

What sed command would you used to delete all lines that don't contain "SPUDS"

Back 401

sed '/SPUDS/!d'

Front 402

What would this sed command do?

sed 's/\([Dd]ie\) or \([Dd]o\)/\2 or \1/'

Back 402

\( \) remembers a pattern in the 'hold buffer'
[Dd]ie represents "die" or "Die"
\2 prints the 2nd remembered pattern

This command will perform the following conversions, if found:

die or do > do or die
Die or do > do or Die
die or Do > Do or die
Die or Do > Do or Die

Front 403

Using sed, how would you surround every instance of the word "hint" in parenthesis?

Back 403

sed 's/hint/(&)/g'

s/search/replace/g - global search and replace
& - represents the search pattern

Front 404

You have a text file containing the poem "The Daffodils", but you don't like the verse that begins "Continuous as the stars that shine". How would you used sed to remove it?

Back 404

sed '/^Continuous/,/bay.$/d' poem.txt

OR

sed '/^Continuous/,/bay.$/!p;d' poem.txt

Front 405

Using sed, you would you remove all lines containing the word "Arse"?

Back 405

sed '/Arse/d'

Front 406

Using sed, you would you show only the lines that contain the word "excellent"?

Back 406

sed '/excellent/!d'

OR

sed '/excellent/p;d'

Front 407

You have a text file that contains a list of files. Using sed, how would you produce a script that can rename all of the files, adding .old to each one?

Back 407

sed '/.*/mv & &.old' > /tmp/script

Front 408

Using sed, how would you capitalize the name "Paul" in an entire text file?

Back 408

sed 's/\&lt;paul /> /directory/file

\&lt; represents the first letter of a word
\u forces upper case

Front 409

What is SIGTERM?

Back 409

SIGTERM is the default 'signal' for the 'kill' command. It sends a 'kill' command to the process rather than to the kernel. The process ends itself. This can be blocked or may fail if the process has hung.

SIGTERM can be specified by using either of these commands:

kill process
pkill processname
pkill -15 processname

Front 410

What does this sed command do?

sed 'N;s/\n //;P;D'

Back 410

Let's break it down:

N read another line (embedded)
s/\n // removes a newline if it starts with a space
P prints up to embedded line
D deletes up to embedded line

This command appends the next line to the current one with "N" command. If the appended line starts with a " ", the newline and " " get removed. If the substitution fails, P prints out the pattern space up to the newline character and D deletes the contents of pattern space up to the newline character.

Front 411

In BASH, how would you easily split a string variable into separate values?

Back 411

Let's say string="one two three four"

user@host$ set -- $string
user@host$ echo $1
one
user@host$ echo $3
three
user@host$ shift
user@host$ echo $1
two
user@host$ echo $@
two three

Front 412

You're using BASH to echo "newline\n", but it does not escape the new line character. How do you get around this?

Back 412

echo -e "newline\n"

Front 413

How do you extract files from a Debian package?

Back 413

Debian packages are 'ar' archives that always contain 3 files: debian-binary, control.tar.gz, and data.tar.gz. To extract...

ar xv package.deb
tar zxvf data.tar.gz

NOTE: You can modify the contents, tar it back up again and use "ar -r package.deb data.tar.gz" to repackage the data.

You can also use "dpkg-deb -x" and "dpkg-deb -b" to extract or build the .deb package.

Front 414

What does this command do?

kill -HUP 123

Back 414

It sends the HUP signal to process 123. This is the same as kill -1, but it's safer because mistyping kill -1 could kill process ID 1.

HUP is the 'hang up' signal. If you send this to many services, they do not terminate, they just reload their configuration.

Front 415

What does this command do?

set c a b

Back 415

It sets the following variable values:

$1 = c
$2 = a
$3 = b

Front 416

If you have a variable $var="one two three", what would the following command do?

set -- $var

Back 416

It would 'unset all positional parameters' resulting in the following values being set:

$1 = one
$2 = two
$3 = three
$# = 3

Front 417

You have a file that is named "-example.txt", and you are trying to delete it. You get the following message:

rm -example.txt
rm: invalid option -- e
Try `rm --help' for more information.

Why can you not delete the file? How do you get around this?

Back 417

When BASH reads the '-' it assumes that '-example.txt' is an option to the rm command, not an argument.

You can work around this in two ways:

rm ./-example.txt

(The filename no longer starts with a '-')

rm -- -example.txt

(The '--' can be used to sign the end of command options)

Front 418

How do you convert a ext2 file system to an ext3 file system?

Back 418

Run the following command as root:

/sbin/tune2fs -j /dev/sd?

Front 419

How can you tell if a program (for example, sendmail) supports TCP Wrappers?

Back 419

ldd `which sendmail` | grep libwrap

Front 420

What would this command do?

ldd `which sendmail` | grep libwrap

Back 420

It checks to see which shared library dependencies are used by sendmail, and then searches the results to see if libwrap is included. This would tell you whether or not sendmail supports TCP Wrappers!

Front 421

List all the Posix character classes and their meanings...

Back 421

[CHAR*] in SET2, copies of CHAR until length of SET1

[CHAR*REPEAT] REPEAT copies of CHAR, REPEAT octal if starting with 0

[:alnum:] all letters and digits

[:alpha:] all letters

[:blank:] all horizontal whitespace

[:cntrl:] all control characters

[:digit:] all digits

[:graph:] all printable characters, not including space

[:lower:] all lower case letters

[:print:] all printable characters, including space

[:punct:] all punctuation characters

[:space:] all horizontal or vertical whitespace

[:upper:] all upper case letters

[:xdigit:] all hexadecimal digits

[=CHAR=] all characters which are equivalent to CHAR

Front 422

What is the file /etc/yp.conf used for?

Back 422

It is the NIS binding configuration file, read by ypbind on startup or when it receives a SIGHUP.

Front 423

Which file contains NIS binding configuration?

Back 423

/etc/yp.conf

Front 424

What does the 'sysctl -a' command do?

Back 424

It displays all kernel parameters currently set.

Front 425

On a GRUB2 system that only has a single OS installed, how do you prevent the system from booting the OS?

Back 425

Hold down the SHIFT key.

Front 426

The following is a sample /etc/inittab:

ca::ctrlaltdel:/sbin/shutdown -r -t 4 now
kb::kbrequest:/bin/echo "Keyboard Request -- edit /etc/inittab to let this work."
pf::powerwait:/etc/init.d/powerfail start
pn::powerfailnow:/etc/init.d/powerfail now
po::powerokwait:/etc/init.d/powerfail stop
sh:12345:powerfail:/sbin/shutdown -h now THE POWER IS FAILING
#
1:2345:respawn:/sbin/mingetty --noclear tty1
2:2345:respawn:/sbin/mingetty tty2
3:2345:respawn:/sbin/mingetty tty3
4:2345:respawn:/sbin/mingetty tty4
5:2345:respawn:/sbin/mingetty tty5
6:2345:respawn:/sbin/mingetty tty6

What does each field represent?

Back 426

They are:
ID number:runlevels:action:process

Actions can be:
respawn
wait
once
boot
bootwait
off
ondemand
initdefault
sysinit
powerwait
powerfail
powerokwait
powerfailnow
ctrlaltdel
kbrequest

Front 427

What are the types of USB Host Controllers?

Back 427

OHCI - open host controller interface [USB1.1 low and full speed] used by most vendors

UHCI - universal host controller interface [USB1.1 low and full speed] - proprietary mainly used by Intel and VIA.

EHCI - enhanced host controller interface [USB2 high speed only - relies on OHCI or UHCI to handle low or full speed]

xHCI - extended host controller interface [USB3 - supports all speeds and makes OHCI/UHCI/EHCI redundant]

Front 428

What command would remove all unused kernel modules?

Back 428

rmmod -a

Front 429

Before adding a new module with "insmod", what command would you used to find information about the module?

Back 429

modinfo

-a show author
-d show description
-p show parameters used by module

example:
modinfo -a /lib/modules/2.6.5-smp/misc/zftape.o

(c) 1998 Mr Bloggs
[e-mail]

Front 430

What command would you use to find out which kernel modules are available for use?

Back 430

There are two methods:

modprobe -l [args]

find /lib/modules/ -exec basename {} \;

NOTE: The arguments to "modprobe -l" don't seem to work in Ubuntu. The book, "LPI Certification in a nutshell" claims that it works, but it doesn't. This may be distribution-specific.

Front 431

How do you force a disk check on the next reboot?

Back 431

sudo touch /forcefsck
shutdown -rF now

Front 432

After removing an network manager from a PC or server, how would you make sure interface eth0 is enabled for DHCP on boot?

Back 432

Edit the file /etc/network/interfaces and add the lines:

auth eth0
iface eth0 inet dhcp

Front 433

Explain the following arguments for the cp command:

-f
-i
-b
-u
-P
-L
-d

Back 433

-f overwrite without prompt
-i interactively prompt to overwrite
-b create backups of existing files
-u update existing files
-P don't follow links, dereference the original and copy the link
-L follow links and reference the original file
-d follow links and make a new link to the original file

[CONFIRM]

Front 434

What's the best way to remember the COM port memory addresses?

Back 434

Addresses either start with a 2 or 3.
COM number matches odd with odd, even with even.
Start with COM2 = 2F8
Alphabetically reversed (F first two, E second two)

COM1 = 3F8
COM2 = 2F8
COM3 = 3E8
COM4 = 2E7

The IRQ is the number +1

COM1 = IRQ4
COM2 = IRQ3
COM3 = IRQ4
COM4 = IRQ3

Front 435

Which envionment variable determines the search path for man pages?

Back 435

MANPATH

Front 436

How would you make a file suid?

Back 436

chmod u+s
OR
chmod 4755

OK, ignore the last three digits, as these set the usual rwx on the file. The 1st digit can be used to setuid, setgid or set the sticky bit. Because file ownership works "user", "group", "others", you setuid by setting the first digit to "4", representing 'user' in octal.

ugo
421

Front 437

How would you set the sticky bit?

Back 437

In the world of 'user', 'group', 'other', the sticky bit is stored in the 'other' section. It looks like this:

-rwxr-xr-t

You can set it like this:
chmod o+t
OR
chmod 1755 foo

NOTE: The letter s was already used by suid, so sticky got the next letter!
NOTE2: The same octal field is used to perform setuid and setgid.

Front 438

How could you get the physical SCSI address of /dev/sda ?

Back 438

scsiinfo /dev/sda

Front 439

Which command would you use to check the signature of a rpm package?

Back 439

rpm --checksig package.rpm

Front 440

How do you reconfigure a debian package?

Back 440

dpkg-reconfigure

Front 441

What is the definition of a daemon

Back 441

It is a process that has no controlling terminal

Front 442

Who can set negative nice values? What do they mean?

Back 442

Only root can give negative nice values. Negative values (from -20 to -1) give higher priority.

Front 443

What are the partition IDs for SWAP and Linux

Back 443

82 = Linux
83 = SWAP

Front 444

Why might you run out of inodes?

Back 444

Too many directories, cross-linked files or small files. (Don't know the 'correct' answer.)

You can count inodes with the command:
df -i

Front 445

What program can be used to configure the X11 server?

Back 445

xf86config
or
XF86Setup

Front 446

In vi 'command mode' how would you move the cursor 7 spaces left

Back 446

7h

Front 447

In vi 'command mode' how would you move the cursor 7 spaces down

Back 447

7j

Front 448

In vi 'command mode' how would you move the cursor 7 spaces right

Back 448

7l

Front 449

In vi 'command mode' how would you move the cursor 7 spaces right?

Back 449

7l

Front 450

Using the setserial command, how would you set the speed to 56k?

Back 450

setserial /dev/ttyS0 spd_hi

Front 451

Using the setserial command, how would you set the speed to 115k?

Back 451

setserial /dev/ttyS0 spd_vhi

Front 452

Using the setserial command, how would you set the speed to 230k?

Back 452

setserial /dev/ttyS0 spd_shi

Front 453

If you set umask to 027, what permissions will the files be?

Back 453

640.
Confused? Read this:
http://teaching.idallen.com/dat2330/04f/notes/umask.txt

The default mode of a directory is 777, while the default mode of a file is 666. The umask applies to the default value.

Front 454

http://www.linux-praxis.de/lpisim/lpi101sim/next.php3

http://www.ibm.com/developerworks/linux/tutorials/l-lpic1101/index.html

Back 454

whatever

Front 455

How do you check the current lilo configuration

Back 455

lilo -q

Front 456

How do you run lilo with a configuration file other than /etc/lilo.conf?

Back 456

lilo -C config_file

Front 457

When do you need to run the lilo command?

Back 457

The lilo command installs a two-stage boot loader. It must be executed any time your boot options (eg kernel, config) change.

Front 458

Recap on the options you know for the command:
dpkg

Back 458

-S search for files installed by package
-L list files in package
-s show status of package
-i install package
-r remove package
--purge remove package and config files
--configure configures an unpacked package

Front 459

How would you convert a .deb package to .rpm format

Back 459

alien --to-rpm package.deb

Front 460

How would you convert an .rpm package to .deb format

Back 460

alien -r package.rpm

Front 461

When setting the bash prompt, what does \W represent?

Back 461

The basename of the working directory.

Front 462

What does it mean to 'export' a variable?

Back 462

A shell variable is not available outside the shell unless it is exported to the environment, becoming an environment variable. All child processes and shells can access exported environment variables.

Front 463

How do you view man pages for a system call named bind?

Back 463

man 2 bind

1 = user programs
2 = system calls
3 = library calls
4 = special files (usually in /dev)
5 = file formats
6 = games
7 = misc
8 = system admin

Front 464

How would you find out which man pages were available for mkfifo?

Back 464

man -wa mkfifo

-w show location, don't print the man pages
-a by default man shows the first available page and exits, but -a shows all pages.

Front 465

'ps' command refresher

Back 465

-a non-daemon processes owned by all users
-f full format, showing arguments to the processes
-l long format including PID, priority etc
-u user format, with usernames and process times
-w wide format
-x include daemons

Front 466

How would you show a process tree with PIDs included

Back 466

pstree -p

Front 467

How would you take 5 process snapshots, one every second, and output to a file?

Back 467

top -bi -n 5 -d 1 > file

-b batch mode
-i ignore idle processes (interesting only)
-n number of times to run
-d delay (sec)

Front 468

Which file shows the paramerets that were passed to the kernel during boot?

Back 468

/proc/cmdline

Front 469

Which dpkg argument scans for partially installed packages and suggests how to fix them?

Back 469

dpkg -C
or
dpkg --audit

Front 470

How would you send a USR1 signal to all Apache httpd processes?

Back 470

The USR1 signal asks Apache to stop allowing new connections, wait for the current ones to die, reread the config files, re-open its log files, and restart the server, allowing for relatively smooth in-production changes.

You can do this with the command:

apachectl -k graceful

You can also do it with the kill command:

kill -s USR1 [pid]

Front 471

Which signal will be sent to a process when you press Ctrl+c on a terminal?

Back 471

SIGINT

Note: Ctrl + \ or Ctrl + Y will send the SIGQUIT signal

Front 472

Which directory is the YUM repository in?

Back 472

/etc/yum.repos.d

Front 473

How would you convert a DOS file to Unix using tr?

Back 473

Tell tr to remove the carriage return:

tr -d '\r' < DOS_file > UNIX_file

Front 474

Where are man files usually located?

Back 474

/usr/share/man

Front 475

Where would you normally find documentation for installed programs?

Back 475

/usr/share/doc/

Front 476

If you install grub using --root-directory=/custom-grub, where will the menu.lst file be created?

Back 476

/custom-grub/boot/menu.lst

Grub treats /custom-grub as / and then creates a sub-directory 'boot' into which it places the menu.lst file.

Front 477

What is the numerical equivalent to SIGHUP

Back 477

1

Front 478

What is the difference between S and K symlinks in /etc/init.d/rc*.d/?

Back 478

Each runlevel has its own rc folder folder in /etc/init.d/ and each of these folders contain symlinks to service files that are located in /etc/init.d.

S symlinks are placed inside any runlevel that the service should be started, and K symlinks should be placed at runlevels where the service should be killed.

There should never be an S and K symlink for a service inside the same runlevel directory.

Front 479

research the whole "cat <<" thing

Back 479

whenever

Front 480

What does the shopt command do?

Back 480

If executed without arguments, shopt displays modifiable shell options.

Other arguments:

-s set
-u unset

Front 481

What is the source command used for?

Back 481

It can read and execute commands from non-executable files.

Front 482

What does this command do?

mke2fs -j /dev/sda1

Back 482

mke2fs is the ext-specific version of mkfs, which has additional options for that particular filesystem.

The -j option instructs mke2fs to add a journal, thus creating an ext3 filesystem

Front 483

Which Linux filesystem cannot dynamically creat inodes?

Back 483

ext2/3.

Other linux filesystems such as Reiser and xfs can create inodes dynamically, but ext2/3 have their allocation set during creation.

Front 484

How could you prevent non-root users from logging into a system

Back 484

create the file /etc/nologin

Front 485

Which "apt-get" option switch will cause "half-installed" packages to complete the installation process?

Back 485

apt-get -f
OR
apt-get --fix-broken

Front 486

When you use apt-get to install a package, in which directory does the downloaded package get stored?

Back 486

/var/cache/apt/archives

Front 487

On a Debian or Ubuntu system, which directory is used to store information about what packages are installed or available, and about what updates are available? (Enter the entire path.)

Back 487

/var/lib/dpkg

Front 488

With dpkg, how do you ensure that you don't overwrite a newer version of the same package?

Back 488

dpkg -R package.deb

Front 489

http://www.studystack.com/flashcard-146269

Back 489

more flashcards

Front 490

http://www.proprofs.com/flashcards/cardshowall.php?title=lpi-101-flash-cards

Back 490

more flashcards

Front 491

How could you monitor the amount of free inodes on /dev/hda3 ?

Back 491

df -i /dev/hda3

Front 492

How would you find out what type of quota is active for user "mcfoo"

Back 492

repquota mcfoo

(The default action of repquota is -u which reports user quotas)

Front 493

In vi command mode, what does ZZ do?

Back 493

This will exit vi, saving changes if there are any

Front 494

What program is used to tune the screen settings after installing X11?

Back 494

xvidtune

Front 495

http://www.linux-praxis.de/lpisim/lpi102sim/index.html

Back 495

102 exam

Front 496

What command will load a kernel module along with all necessary dependencies?

Back 496

modprobe

Front 497

You wish to load a module, but you don't know which options can be used. How do you find out?

Back 497

modinfo

Front 498

When submitting a print job using lpr, how do you print 5 copies?

Back 498

lpr -5 -Pprinter /tmp/file

Front 499

Which file contains the welcome message being displayed by getty before the login?

Back 499

/etc/issue

Front 500

How do you check if the file /tmp/foo exists and is owned by the user.

Back 500

test -O /tmp/foo

Front 501

What would this command do?
userdel -r foo

Back 501

It removes the user 'foo' and deletes his home directory.

Front 502

In the latest versions of Linux, what two utilities have replaced the "scsi_info" utility that used to be in older versions of Linux?

Back 502

sginfo & lsscsi

Front 503

On a modern Linux system, which program monitors for hotplug events?

Back 503

udev

Front 504

http://www.proprofs.com/flashcards/cardshowall.php?title=lpi-101-flash-cards

Back 504

more flashcards

Front 505

http://www.penguintutor.com/cgi-bin/quiz/index.pl

Back 505

practise exams