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How to create command aliases

Aliases in the Unix/Linux operating system provide shortcuts that can save you typing, let you build your own powerful commands, and make your command line life easier.

I've found it very helpful to create aliases to make my command line Unix/Linux life easier. For instance, instead of always typing

ls -al

to get a directory listing, I've created an alias so I only have to type this: "l" (That's the lower case letter "L".)

Using aliases like this you can create anything from simple shortcuts like this to powerful custom commands.
How to create aliases

Creating aliases is very easy. You can either enter them at the command line as you're working, or more likely, you'll put them in one of your startup files, like your .bashrc file, so they will be available every time you log in.

I created the l alias above by entering the following command into my .bashrc file:

alias l="ls -al"

As you can see, the syntax is very easy:

   1. Start with the alias command
   2. Then type the name of the alias you want to create
   3. Then an = sign, with no spaces on either side of the =
   4. Then type the command (or commands) you want your alias to execute when it is run. This can be a simple command, or can be a powerful combination of commands.

Sample aliases
To get you going, here is a list of sample aliases I use all the time. I've pretty much just copied them here from my .bashrc file:

alias l="ls -al"
alias lm="ls -al|more"
alias html="cd /web/apache/htdocs/devdaily/html"
alias logs="cd /web/apache/htdocs/devdaily/logs"
alias qp="ps auxwww|more"
alias nu="who|wc -l"
alias aug="ls -al|grep Aug|grep -v 2002"

As you can see, you can get as creative as you want, and pipe commands together to do just about anything. In the last alias shown I've actually combined three Unix commands in a row into one alias to get the output I want.

Because the Unix shell is very programmable and because the output of commands is very consistent and reliable, you can create your own aliases (or macros if you prefer) to do just about anything.


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