[ILUG] File Difference

[Padraig Brady]

Kieran OSullivan wrote:
> I have 2 files a.txt and b.txt. b.txt is a subset of a.txt however they are not sorted in the same order e.g. "xyz.com" will be in b.txt on line 20 and in a.txt on line 30.  I have tried using a diff command such as
> 
> diff --side-by-side --suppress-common-lines -i a.txt b.txt
> 
> This appeared to work until I took a good look at my results.
> 
> What I am looking for is a command or program, which will look at a.txt and b.txt, eliminate all the stuff in b.txt regardless of its position and display the result.
> 
> E.g a.txt ={a,b,c,d} b.txt={a,b,c}
> $command a.txt b.txt 
> displays {d}

Well if you don't mind uniqifyind lines within files:

cat a.txt b.txt | sort | uniq -u

Otherwise you need to use comm

Padraig.