Aliases

Linux

Tricks

When we often have to use a single big command multiple times, in those cases, we create something called as alias for that command. An alias instructs the shell to replace one string with another string while executing the commands.

An alias can be set by using the command alias or it can be persisted by using the files ~/.bash_aliases or ~/.bashrc.

alias command

The alias command is used to create or redefine aliases. It can also be used to write existing aliases to standard output. An alias definition affects the current shell execution environment and the execution environments of the subshells of the current shell.

Usage

alias [-p] [alias-name[=value] ... ]

Create an alias for a commonly used ls command:

alias lf="ls -CF"

Write the definition of the lf alias to standard output:

alias lf

Write all the defined aliases to standard output:

alias

alias -p

unalias command

The unalias command is used to remove the definition for each alias name specified. The aliases are removed from the current shell execution environment.

Usage

unalias alias-name...

unalias -a

Remove the definition of all aliases:

unalias -a

Remove the definition of the lf alias:

unalias lf

bash_aliases file

Aliases can be persisted in the file ~/.bash_aliases. The content of the file is a series of calls the alias command that will be executed on system startup.

Example

# Copies the standard input to the clipboard
# Usage: cat file | copy
alias copy='xsel -ib'

# Mount terminus-nas network share to /media/terminus
alias terminus='sudo mount -t cifs -o uid=1000,gid=1000,username=ubuntu //192.168.1.200/terminus-nas /media/terminus'

# Unmount terminus-nas network share from /media/terminus
alias uterminus='sudo umount /media/terminus'

bashrc file

Aliases can be persisted in the ~/.bashrc file the same way they are persisted in the ~/bash_aliases file.