Linux Command Cheat Sheet

Basic Linux commands

Command	Description
`ls`	Lists all files and directories in the present working directory
`ls -R`	Lists files in sub-directories as well
`ls -a`	Lists hidden files as well
`ls -al`	Lists files and directories with detailed information like permissions,size, owner, etc.
`cd or cd ~`	Navigate to HOME directory
`cd ..`	Move one level up
`cd`	To change to a particular directory
`cd /`	Move to the root directory
`cat > filename`	Creates a new file
`cat filename`	Displays the file content
`cat file1 file2 > file3`	Joins 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_name`	Renames the file to a new filename
`sudo`	Allows regular users to run programs with the security privileges of the superuser or root
`rm filename`	Deletes a file
`man`	Gives help information on a command
`history`	Gives a list of all past commands typed in the current terminal session
`clear`	Clears the terminal
`mkdir directoryname`	Creates a new directory in the present working directory or a at the specified path
`rmdir`	Deletes a directory
`mv`	Renames a directory
`pr -x`	Divides the file into x columns
`pr -h`	Assigns a header to the file
`pr -n`	Denotes the file with Line Numbers
`lp -nc , lpr c`	Prints "c" copies of the File
`lp-d lp-P`	Specifies name of the printer

`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

Command	Description
`ls -l`	to show file type and access permission
`r`	read permission
`w`	write permission
`x`	execute permission
`-=`	no permission
`chown user`	For changing the ownership of a file/directory
`chown user:group filename`	change the user as well as group for a file or directory

Command	Description
`echo $VARIABLE`	To display value of a variable
`env`	Displays all environment variables
`VARIABLE_NAME= variable_value`	Create a new variable
`unset`	Remove a variable
`export Variable=value`	To set value of an environment variable

Command	Description
`ssh username@ip-address or hostname`	login into a remote Linux machine using SSH
`ping hostname="" or =""`	To ping and Analyzing network and host connections
`dir`	Display files in the current directory of a remote computer
`cd "dirname"`	change directory to "dirname" on a remote computer
`put file`	upload 'file' from local to remote computer
`get file`	Download 'file' from remote to local computer
`quit`	Logout

Command	Description
`bg`	To send a process to the background
`fg`	To run a stopped process in the foreground
`top`	Details on all Active Processes
`ps`	Give the status of processes running for a user
`ps PID`	Gives the status of a particular process
`pidof`	Gives the Process ID (PID) of a process
`kill PID`	Kills a process
`nice`	Starts a process with a given priority
`renice`	Changes priority of an already running process
`df`	Gives free hard disk space on your system
`free`	Gives free RAM on your system

Command	Description
`i`	Insert at cursor (goes into insert mode)
`a`	Write after cursor (goes into insert mode)
`A`	Write at the end of line (goes into insert mode)
`ESC`	Terminate insert mode
`u`	Undo last change
`U`	Undo all changes to the entire line
`o`	Open a new line (goes into insert mode)
`dd`	Delete line
`3dd`	Delete 3 lines
`D`	Delete contents of line after the cursor
`C`	Delete contents of a line after the cursor and insert new text. Press ESC key to end insertion.
`dw`	Delete word
`4dw`	Delete 4 words
`cw`	Change word
`x`	Delete character at the cursor
`r`	Replace character
`R`	Overwrite characters from cursor onward
`s`	Substitute one character under cursor continue to insert
`S`	Substitute entire line and begin to insert at the beginning of the line
`~`	Change case of individual character