grouping and grep only different lines

[babeo]

Hi,
I have a file contain repeating data, eg
[3311111450]
[3311111450]
[40222221100]
[40222221100]
[40222221100]
[66666221100]
[66666221100] and so on..

I want to cat the file but only display 1 line for each group
[3311111450]
[40222221100]
[66666221100] and so on.

Is there any command can do the grouping by line?
Thanks

 

[SamBones]

Try this...

[tt]
sort file.dat | uniq
[/tt]

 

[babeo]

Woah Hooo!!

It works perfect. Thanks a lot Sam.