Bash Commands

uname -a

Show system and kernel

head -n1 /etc/issue

Show distri­bution

mount

Show mounted filesy­stems

date

Show system date

uptime

Show uptime

whoami

Show your username

man command

Show manual for command

Bash Shortcuts

CTRL-c

Stop current command

CTRL-z

Sleep program

CTRL-a

Go to start of line

CTRL-e

Go to end of line

CTRL-u

Cut from start of line

CTRL-k

Cut to end of line

CTRL-r

Search history

!!

Repeat last command

!abc

Run last command starting with abc

!abc:p

Print last command starting with abc

!$

Last argument of previous command

ALT-.

Last argument of previous command

!*

All arguments of previous command

^abc^123

Run previous command, replacing abc with 123

Bash Variables

env

Show enviro­nment variables

echo $NAME

Output value of $NAME variable

export NAME=value

Set $NAME to value

$PATH

Executable search path

$HOME

Home directory

$SHELL

Current shell

IO Redire­ction

cmd < file

Input of cmd from file

cmd1 <(cmd2)

Output of cmd2 as file input to cmd1

cmd > file

Standard output (stdout) of cmd to file

cmd > /dev/null

Discard stdout of cmd

cmd >> file

Append stdout to file

cmd 2> file

Error output (stderr) of cmd to file

cmd 1>&2

stdout to same place as stderr

cmd 2>&1

stderr to same place as stdout

cmd &> file

Every output of cmd to file

cmd refers to a command.

Pipes

cmd1 | cmd2

stdout of cmd1 to cmd2

cmd1 |& cmd2

stderr of cmd1 to cmd2

Command Lists

cmd1 ; cmd2

Run cmd1 then cmd2

cmd1 && cmd2

Run cmd2 if cmd1 is successful

cmd1 || cmd2

Run cmd2 if cmd1 is not successful

cmd &

Run cmd in a subshell

Directory Operations

pwd

Show current directory

mkdir dir

Make directory dir

cd dir

Change directory to dir

cd ..

Go up a directory

ls

List files

ls Options

-a

Show all (including hidden)

-R

Recursive list

-r

Reverse order

-t

Sort by last modified

-S

Sort by file size

-l

Long listing format

-1

One file per line

-m

Comma-­sep­arated output

-Q

Quoted output

Search Files

grep pattern files

Search for pattern in files

grep -i

Case insens­itive search

grep -r

Recursive search

grep -v

Inverted search

grep -o

Show matched part of file only

find /dir/ -name name*

Find files starting with name in dir

find /dir/ -user name

Find files owned by name in dir

find /dir/ -mmin num

Find files modifed less than num minutes ago in dir

whereis command

Find binary / source / manual for command

locate file

Find file (quick search of system index)

File Operations

touch file1

Create file1

cat file1 file2

Concat­enate files and output

less file1

View and paginate file1

file file1

Get type of file1

cp file1 file2

Copy file1 to file2

mv file1 file2

Move file1 to file2

rm file1

Delete file1

head file1

Show first 10 lines of file1

tail file1

Show last 10 lines of file1

tail -F file1

Output last lines of file1 as it changes

Watch a Command

watch -n 5 'ntpq -p'

Issue the 'ntpq -p' command every 5 seconds and display output

Process Management

ps

Show snapshot of processes

top

Show real time processes

kill pid

Kill process with id pid

pkill name

Kill process with name name

killall name

Kill all processes with names beginning name

Nano Shortcuts

Files

Ctrl-R

Read file

Ctrl-O

Save file

Ctrl-X

Close file

Cut and Paste

ALT-A

Start marking text

CTRL-K

Cut marked text or line

CTRL-U

Paste text

Navigate File

ALT-/

End of file

CTRL-A

Beginning of line

CTRL-E

End of line

CTRL-C

Show line number

CTRL-_

Go to line number

Search File

CTRL-W

Find

ALT-W

Find next

CTRL-\

Search and replace

More nano info at:

http:/­/ww­w.n­ano­-ed­ito­r.o­rg/­doc­s.php

Screen Shortcuts

screen

Start a screen session.

screen -r

Resume a screen session.

screen -list

Show your current screen sessions.

CTRL-A

Activate commands for screen.

CTRL-A c

Create a new instance of terminal.

CTRL-A n

Go to the next instance of terminal.

CTRL-A p

Go to the previous instance of terminal.

CTRL-A "

Show current instances of terminals.

CTRL-A A

Rename the current instance.

More screen info at:

http:/­/ww­w.g­nu.o­rg­/so­ftw­are­/sc­reen/

File Permis­sions

chmod 775 file

Change mode of file to 775

chmod -R 600 folder

Recurs­ively chmod folder to 600

chown user:group file

Change file owner to user and group to group

File Permission Numbers

First digit is owner permis­sion, second is group and third is everyone.

Calculate permission digits by adding numbers below.

4

read (r)

2

write (w)

1

execute (x)