Aliases in bash


How to set and unset an alias in bash

1. Listing aliases

To list the currently set aliases use the alias command. On Ubuntu this prints something similar to:

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alias alert='notify-send --urgency=low -i "$([ $? = 0 ] && echo terminal || echo error)" "$(history|tail -n1|sed -e '\''s/^\s*[0-9]\+\s*//;s/[;&|]\s*alert$//'\'')"'
alias egrep='egrep --color=auto'
alias fgrep='fgrep --color=auto'
alias grep='grep --color=auto'
alias l='ls -CF'
alias la='ls -A'
alias ll='ls -alF'
alias ls='ls --color=auto'

As we can see by default there are already some useful aliases set:

2. Setting your own alias

As an example lets create an alias lh for the command ls -lh, that is the list command with the ‘long’ and ‘human-readable’ parameters. To do this run:

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alias lh=`ls -lh`

The alias will exist for the lifetime of the current terminal session.

3. Setting an alias permanently

To create a permanent alias modify your .bashrc file (located in your home directory) and append the command to set your custom alias.

4. Unset an alias

To unset an alias use the unalias command. To unset the alias we created in section 2 run:

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unalias lh
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