Unix Commands

Front 1

lists contents of current working directory

Back 1

ls

Front 2

lists all files in working directory including hidden

Back 2

ls -a

Front 3

make a directory

Back 3

mkdir

Front 4

change directory

Back 4

cd

Front 5

name of current directory

Back 5

.

Front 6

name of parent directory

Back 6

..

Front 7

print working directory

Back 7

pwd

Front 8

home directory

Back 8

~

Front 9

command to make a copy of file1 in the current working directory and call it file2

Back 9

cp file1 file2

Front 10

move (or rename) file1 to file2

Back 10

mv file1 file2

Front 11

remove a file

Back 11

rm

Front 12

remove a directory

Back 12

rmdir

Front 13

clear terminal window

Back 13

clear

Front 14

display contents of a file on the screen

Back 14

cat

Front 15

write the contents of a file onto the screen a page at a time

Back 15

less

Front 16

write the first ten lines of a file onto the screen

Back 16

head

Front 17

write the last ten lines of a file on the screen

Back 17

tail

Front 18

finding a word using less command

Back 18

less (file.ext); /phraseofinterest

Front 19

result of writing grep science science.txt

Back 19

prints all lines with the word “science” in it from science.txt (case-sensitive)

Front 20

ignore case distinctions w grep

Back 20

grep -i

Front 21

search for phrase “spinning top” in science.txt using grep

Back 21

grep -i 'spinning top'

Front 22

option to use grep to display lines that do not match

Back 22

grep -v

Front 23

option to precede each matching line in grep with line number

Back 23

grep -n

Front 24

word count utility

Back 24

wc -w

Front 25

count lines in a text

Back 25

wc -l

Front 26

stopping a process

Back 26

Control-d

Front 27

effect of cat command without specifying a file to read

Back 27

reads standard input and displays when process is stopped

Front 28

redirect output of a function

Back 28

>

Front 29

appends standard output to a file

Back 29

>>

Front 30

concatenate list1 and list2 to biglist

Back 30

cat list1 list2 > biglist

Front 31

command for alphabetically or numerically sorting a list

Back 31

sort

Front 32

direct output from one command into another

Back 32

|

Front 33

wildcard character

Back 33

*

Front 34

wildcard for one character only

Back 34

?

Front 35

gives a one-line description of the command

Back 35

whatis

Front 36

gives commands with a word in their page header

Back 36

apropos keyword

Front 37

meaning of string giving permissions in ls -l

Back 37

taken in 3 groups of 3. left group gives permissions for owner of file. Middle group gives permissions for group owning the file. Rightmost group gives permissions for all others.

Front 38

command to change permissions on a file

Back 38

chmod

Front 39

remove read write and execute permissions for group and others on a file called “biglist”

Back 39

chmod go-rwx biglist

Front 40

shows information about processes, with process identifier number and status

Back 40

ps

Front 41

to background a process

Back 41

Type & at the end of the command

Front 42

suspend a process

Back 42

[ctrl]z

Front 43

background an active process

Back 43

bg

Front 44

see the list of processes running, including backgrounded processes

Back 44

jobs

Front 45

to restart (foreground) a suspended process

Back 45

fg %jobnumber

Front 46

foregrounds last suspended process

Back 46

fg

Front 47

kills a process running in the foreground

Back 47

[ctrl]c

Front 48

kill a suspended or background process

Back 48

kill %jobnumber or processnumber

Front 49

good for killing a process that is refusing to be killed

Back 49

Kill -9 processnumber

Front 50

reports on space left in the file system

Back 50

df

Front 51

outputs the number of kilobytes used by each subdirectory

Back 51

du

Front 52

compress a file (put into gzip)

Back 52

gzip file.ext

Front 53

expand a gzipped file

Back 53

gunzip file.ext.gz

Front 54

file to read gzipped files without first uncompressing them

Back 54

zcat file.ext.gz

Front 55

classifies named files according to the type of data they contain

Back 55

file

Front 56

compares contents of 2 files and displays the differences

Back 56

diff file1 file2

Front 57

searches through files and directories for files with a given attribute

Back 57

find

Front 58

search for all files with the ext .txt, starting at the current directory and working through all sub-directories

Back 58

Find . -name “*.txt” -print

Front 59

find files over 1Mb in size and display as a long listing

Back 59

Find . -size +1M -ls

Front 60

gives an ordered list of all commands entered

Back 60

history

Front 61

package search command (debian)

Back 61

Apt-get update; apt-cache search string

Front 62

package installation tool (debian)

Back 62

Apt-get update; apt-get install package_name

Front 63

install package on Debian (low level, without dependency resolution)

Back 63

dpkg –install package_file

Front 64

remove a package

Back 64

Apt-get remove package_name

Front 65

commands for updating system with latest packages

Back 65

Apt-get update; apt-get upgrade

Front 66

list of all packages installed on system

Back 66

dpkg –list

Front 67

specify whether a given package is installed

Back 67

dpkg –status package_name

Front 68

display a description of the package

Back 68

Apt-cache show package_name

Front 69

determine which package is responsible for the installation of a particular file

Back 69

dpkg –search file_name

Front 70

mount a filesystem

Back 70

mount

Front 71

unmount a filesystem

Back 71

unmount

Front 72

partition table manipulator

Back 72

fdisk

Front 73

check and repair a filesystem

Back 73

fsck

Front 74

format a floppy disk

Back 74

fdformat

Front 75

create a filesystem

Back 75

mkfs

Front 76

write block-oriented data directly to a device

Back 76

dd

Front 77

create an ISO 9660 image file

Back 77

genisoimage (mkisofs)

Front 78

write data to optical storage media

Back 78

wodim (cdrecord)

Front 79

calculate an md5 checksum

Back 79

md5sum

Front 80

file listing devices (typically hard disk partitions) that are to be mounted at boot time

Back 80

/etc/fstab

Front 81

action of mount command without arguments

Back 81

will display a list of filesystems currently mounted

Front 82

keystroke for command completion

Back 82

tab key