Unix Commands

Front 1

Copy files

Back 1

cp <filename> <new location>

Front 2

Move files

Back 2

mv <filename> <new location>

Front 3

Rename files

Back 3

mv <old filename> <new filename>

Front 4

Delete files

Back 4

rm <filename>

rm <filename> -f
to delete without having to answer y/n if you're sure

note: no recycle bin or undo for these deletions

Front 5

Create directories

Back 5

mkdir <directory name>

Front 6

Delete directories

Back 6

rm -rf <directory name>

Front 7

Change directory

Back 7

cd

Front 8

Edit text files

Back 8

vi <filename>

or

gedit <filename>
This will open text files in Gedit.

Front 9

View text files

Back 9

less <filename>

Use cursor keys up and down to move through document. Q to quit.

Front 10

Print text files

Back 10

lpr <filename>

Front 11

Compare files

Back 11

diff <file1> <file2>

Front 12

Find files

Back 12

find -name <filename>

Front 13

Check disk integrity

Back 13

fsck

This is a system command and can be run only on a disk that isn’t currently in use. To scan the main parti-
tion, you’ll need to boot from the installation CD and select the rescue option. Then issue the fsck command.

Front 14

View network settings

Back 14

ifconfig

Front 15

Check a network connection

Back 15

ping <address>

Front 16

View a network route

Back 16

tracepath <address>

Front 17

Clear screen

Back 17

clear

Front 18

Get help

Back 18

man <command>

or

info <command>

Front 19

Quit

Back 19

exit

Front 20

List files in current directory

Back 20

ls

Front 21

ls options ("flags" or "switches")

Back 21

ls -m fit as many possible on one line
ls --help shows all options
ls -l "long" permissions, owners, etc.
ls -a shows hidden files
ls -lh h = human readable (kilobytes and megabytes instead of bytes)

Front 22

Copy a directory and its contents (and all directories and files w/in that directory)

Back 22

cp -r

-r stands for "recursive"

Front 23

Reference current directory
Reference parent directory

Back 23

.
..
For example cd ..
will go up a directory. . or ./ references current dictory.

Front 24

Working with spaces

Back 24

mv "picture from germany.jpg" mydirectory/

or

mv picture\ from\ germany.jpg mydirectory/

Front 25

Create a directory and a new directory to contain it Fwd:

Back 25

Use the -p command option. E.g.

mkdir -p flowers/daffodil

Front 26

File permissions
ls -l

Back 26

r = read
w = write
x = execute (or for directories, access)

- --- --- ---
type of file; owner; group; everyone else

e.g. #1
-rw--r--r--

- = standard file
rw- = owner can read/write
r-- = group can read only
r-- = everyone else can read only

e.g. #2
drwxr-xr-x

d = directory
rwx = read/write/access; with directories x means you can access the directory)
r-x = group can read/access
r-- = everyone else can read/access


File Type Codes:

Standard file
-

Standard directory
d

Symbolic link (a shortcut to another file)
l

Named pipe (a file that acts as a conduit for data between two programs)
p

Socket (a file designed to send and receive data over a network)
s

Character device (a hardware device driver, usually found in /dev)
c

Block device (a hardware device driver, usually found in /dev)
b

Front 27

Change file permissions: Everyone can read and write to it

Back 27

chmod a+rw <file>

add read write permissions (rw)
to all users (a)

Front 28

Change file permissions: Take away ability of all users to write

Back 28

chmod a-w <file>

take away write (w) permissions from all (a) users, but leave everything else as is

Front 29

Change file permissions: Add read/write permissions for...
- owner
- group
- non-owner non-group memebers
- all

Back 29

- chmod u+rw <file>
- chmod g+rw <file>
- chmod o+rw <file>
- chmod a+rw <file> OR chmod +rw

u = user/owner
g = group
o = others
a = all (default)

Front 30

Change file permissions: Make a program downloaded from the internet executable

Back 30

chmod u+x <program>

Front 31

Change file ownership (e.g. to frank)

Back 31

sudo chown frank myfile

Front 32

vimtutor

Back 32

learn vim

Front 33

whereis

Back 33

e.g. whereis mysql
... will show you where mysql lives in the directories.

Front 34

log in to MySQL

Back 34

mysql -h host -u user -p
(wait for the password prompt)
note: W/ localhost, you can omit -h

Front 35

(mysql) create a databse

Back 35

CREATE DATABASE dbname;

Front 36

(mysql) switch default database for session

Back 36

USE dbname

(no semicolon is used with the USE statement because it's a client-based SQL statement)

Front 37

(mysql) create table

Back 37

CREATE TABLE tblname (
field TYPE,
field TYPE);

Front 38

(mysql) view structure of a table

Back 38

DESCRIBE table;

Front 39

make changes to a table (mysql)

Back 39

ALTER TABLE tablename
CHANGE COLUMN name newname details,
ADD COLUMN name details;

Front 40

get a list of databases (mysql)

Back 40

SHOW DATABASES;

Front 41

get a list of tables in a database (mysql)

Back 41

SHOW TABLES;

(to change databases do
USE dbname
then
SHOW TABLES;)

(to see tables in another db without changing databases do this
SHOW TABLES FROM dbname;)

Front 42

add rows of data to a table

Back 42

INSERT INTO tablename
(name, title, describtion)
VALUES ('Tom', 'Executive Director', 'the boss');

note: if you're going to enter values for all the columns in the table, you don't need to name the columns, but you must list the data in the same order in which the columns are listed in the table.

Front 43

basic SELECT statements

Back 43

SELECT * FROM books;

or

SELECT book_id, title, description
FROM books
WHERE genre = 'novel';

Front 44

inner join
and
concatenate

Back 44

SELECT book_id, title, pub_year,
CONCAT(author_first, ' ', author_last) AS author
FROM books
JOIN authors USING(author_id)
WHERE author_last = 'Greene';

if joined fields have different names use a different clause/method:

JOIN authors ON (author_id = writer_id)

Front 45

get ID of last inserted record

Back 45

SELECT LAST_INSERT_ID();