[foamy]

Hi,

I would like to scan a large text file (50MB) and remove all lines conating a specific string, lets say "aaaaa". I don't really care about saving those lines, just getting rid of them from the original file.

I tried using the little knowledge of grep that I have, but all I ended up with was a file containing the lines I didn't want.

Any suggestions?

TIA

[Arkham_c]

This should work:

Code:
grep -v "pattern" file > output.txt

That will find all lines not containing pattern and will redirect them into the file output.txt

[foamy]

I found a perl tutorial that gave me some hints and ended up with

perl -pi.bak -e 's/.*G{5,}.*$//; s/.*C{5,}.*$//; s/.*A{5,}.*$//; s/.*T{5,}.*$//; s/^\s*$//' filename

I'm sure there is a more elegant way to do it, but it worked in removing all lines with 5 or more G A T or C.

thanks

[Wevah]

DNA?

[Wevah]

Why not just:

perl -pi.bak -e 's/^.*[GCAT]{5,}.*$//;' filename

?

[foamy]

Yep DNA.

I spent the last hour trying to get that exact syntax to work, but gave up and just strung them all together one after another.

My knowledge of regular expressions is only as good as the tutorial I'm reading at the time!

Thanks for showing me the elegant way of getting it done...now if I could just get some Linux code to compile I'd be home free.

[Wevah]

Word; glad I could be of some help!