Linux commands cheat sheet

 Linux commands cheat sheet

Did you recognize that there are actually many Linux commands? Even on a bare-bones Linux server install there are easily over 1,000 different commands.
The interesting thing is that the majority of people only have to use an awfully small subset of these commands. Below you’ll find a Linux “cheat sheet” that breaks down a number of the foremost commonly used commands by category.

Enjoy!

linux commands cheat sheet

Basic Linux commands

CommandDescription
lsLists all files and directories in the present working directory
ls-RLists files in sub-directories as well
ls-aLists hidden files as well
ls-alLists files and directories with detailed information like permissions,size, owner, etc.
cd or cd ~Navigate to HOME directory
cd ..Move one level up
cdTo change to a particular directory
cd /Move to the root directory
cat > filenameCreates a new file
cat filenameDisplays the file content
cat file1 file2 > file3Joins two files (file1, file2) and stores the output in a new file (file3)
mv file "new file path"Moves the files to the new location
mv filename new_file_nameRenames the file to a new filename
sudoAllows regular users to run programs with the security privileges of the superuser or root
rm filenameDeletes a file
manGives help information on a command
historyGives a list of all past commands typed in the current terminal session
clearClears the terminal
mkdir directorynameCreates a new directory in the present working directory or a at the specified path
rmdirDeletes a directory
mvRenames a directory
pr -xDivides the file into x columns
pr -hAssigns a header to the file
pr -nDenotes the file with Line Numbers
lp -nc , lpr cPrints “c” copies of the File
 lp-d lp-P Specifies name of the printer
apt-get Command used to install and update packages
mail -s 'subject' -c 'cc-address'   -b 'bcc-address' 'to-address' Command to send email
mail -s "Subject" to-address < Filename Command to send email with attachment

SYSTEM INFORMATION

Display Linux system information

uname -a

Display kernel release information

uname -r

Show which version of redhat installed

cat /etc/redhat-release

Show system host name

hostname

Display the IP addresses of the host

hostname -I

 Show this month’s calendar

cal

Display who is online

w

Bash Commands

uname -a  Show system and kernel

head -n1 /etc/issue  Show distri bution

mount  Show mounted filesy ‐stems

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 enviro nment variables

echo $NAME  Output value of $NAME variable

Bash Variables (cont)

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- sep arated 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

Search Files (cont)

find /dir/ -user name Find files owned by name in dir

find /dir/ -mmin num  Find files modified 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   Concat enate 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

Screen Shortcuts

Screen  Start a screen session.

screen –r  Resume a screen session.

Screen Shortcuts (cont)

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.

File Permissions

chmod 775 file      Change mode of file to 775

chmod -R 600 folder  Recurs ively 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)