Basic_Linux_Command

\#linux

Basic

Command	Description	Example
`id`	see the identity of your current account, and the your group memberships	`id`
`groups`	To list the names of the groups that you have memberships	`groups`
`man`	Display the manual page for a particular command	`man <command>`
`clear`	Clear the terminal screen	`clear`
`history`	View previous commands	`history`
`alias`	View aliases / Create alias	`alias`
`alias <name>=<command>`
`pwd`	Print current directory absolute path	`pwd`
`ls`	List files in specified directory (current directory by default)	`ls`
`ls -al`
`cd`	Change your current directory location	`cd <dir>`
`cd ..`

Quoting	Description
`'...'`	Treat as normal string
`"..."`	Treat as formatted string, available variable substitution
`...`	Run command within ``

Operator	Description	Example
`#`	Comment	`# comment`
`$`/`${}`	Environment variable	`$PATH`/`${PATH}`
`$()`	Run command within the bracket	`echo "current working dir: $(pwd)"`

Command	Description	Example
`touch`	Create a file	`touch <file>`
`cp`	Copy a file	`cp <file> <new file>`
`cp -r <dir> <new dir>`
`mv`	Move a file	`mv <file> <new loc>`
`mv -r <dir> <new dir>`
`rm`	Delete a file	`rm <file>`
`rm -r <dir>`
`mkdir`	Make a new subdirectory	`mkdir <dir>`
`chgrp`	change the group owner of a file the user owns
`chown`	change user ownership of a file (only be used by the root user)
`chmod`	Change permission	`chmod <permission> <file>`
`umask`	determine the default permissions that are set when a new file or directory is created

Command	Description	Example
`which`	Find all execute location	`which <command>`
`whereis`	Find execute / binary / source file location	`whereis <command>`
`locate`	Find any file as long as the user has permission to access	`locate <command>`
`updatedb`	Immediately update the locate database (normally by root user)	`updatedb <command>`
`find`	Search file	`find / -type d`

Command	Description	Example
`read`	Read user input	`read <var name>`
`read -p "message" <var name>`
`echo`	Output the string or value of a variable	`echo <string>`
`strings`	Output the strings in a file	`strings <file>`
`cat`	Output the content of a file	`cat <file>`
`head`	Output first 10 line of a file	`head <file>`
`tail`	Output first 10 line of a file	`tail <file>`
`more`
`less`	View file	`less <dir>`
`file`	Output description of a file	`file <file>`
`test`
`expr`	evaluates an expression and outputs the corresponding value
`sort`
`uniq`
`newgrp`
`grep`	Search text	`grep <string> <file>`
`grep -E <regex> <file>`
`tr`
`sed`
`wc`	Word count	`wc -l <file>`
`cut`	Cut	`cut -d <char> -f1`

When you specify the location of a file or directory from the top level directory (called the root directory) through all of the sub directories to the file or directory.
Absolute paths start with /.

When you specify the location of a file or directory relative to the current directory.
Relative paths do not start with /.

Last modified: 12 June 2025