adding alias for commands in Bash

Courtesy to hypexr.org.

If you have used UNIX for a while, you will know that there are many commands available and that some of them have very cryptic names and/or can be invoked with a truckload of options and arguments. So, it would be nice to have a feature allowing you to rename these commands or type something simple instead of a list of options. Bash provides such a feature : the alias .
Aliasses can be defined on the command line, in .bash_profile, or in .bashrc, using this form :

alias name=command

This means that name is an alias for command. Whenever name is typed as a command, Bash will substitute command in its place. Note that there are no spaces on either side of the equal sign. Quotes around command are necessary if the string being aliassed consists of more than one word. A few examples :

• alias ls='ls -aF --color=always'
  
• alias ll='ls -l'
  
• alias search=grep
  
• alias mcd='mount /mnt/cdrom'
  
• alias ucd='umount /mnt/cdrom'
  
• alias mc='mc -c'
  
• alias ..='cd ..'
  
• alias ...='cd ../..'

The first example ensures that ls always uses color if available, that dotfiles are listed as well,that directories are marked with a / and executables with a *. To make ls do the same on FreeBSD, the alias would become :

• alias ls='/bin/ls -aFG'

To see what aliasses are currently active, simply type alias at the command prompt and all active aliasses will be listed. To "disable" an alias type unalias followed by the alias name.

One more important thing. After you have added alias in .bashrc, you need to inform your system about the changes and hence execute the following command:

• source .bashrc