Archive for August, 2003

In DOS, a godsend in DOS 5+ was the DOSKEY command. I remember putting this in my autoexec.bat file

doskey dd=dir/w

Everytime I’d typ dd at the prompt, I’d get the wide directory listing. I used it so much in fact, that I even have it in my Windows XP PATH variable in Environment Variables. Only I use it with ls instead of dd. I’ve been using Linux way too long. ;)

But regardless, that is an alias in DOS. Today, we”re going to look at aliasing commands in Linux. I learned the aliasing trick (seen below) from ComputerWorld magazine and it is one of the most effortless things to do to avoid repetitive typing. That, and who can remember all of those god-forsaken attributes?

The syntax of an alias command looks something like this:

alias aliasname='command'

One particulalry usefulcommand that I use quite often is the ‘du’ command. This command checks on disk usage and returns quite a bit of useful information. With the -c attribute, you get a complete listing. Add a -k to the ccmmand for a listing in kilobytes. Finally, grab only the most ciritical data with a -s for summary. What you have now is a ‘ducks’ alias.

alias ducks='du -cks *'

Now that’s good and will give us a bunch of information. But if you really want to make this baby dance, pipe it to a sort command to list them in some sembalnce of order. To do this, we will use the ‘sort’ command. Do I need to explain what this does? :rolleyes: With an -rn tag, we sort in Ascending (Reverse) order by numerical value. Our alias now looks like this:

alias ducks='du -cks * | sort -rn'

Now all you have to type in at a command prompt is

$ ducks

and you will get a nice concise summary of directory usage. It descends recursively into subdirectories as well.

It will look something like this

$ cd /home
$ ducks
98800 user1
78430 user2
128053 user3

For more information on these commands, visit the links below:

du – man du sort – man sort

Enjoy!