grep

AndrewJS · 07-03-2011, 05:32 PM

I normally use 'grep' to provide parse out all unwanted extensions and so on by specifying the extension that I do want...
for example of I have list of files with many different extension types such as .dat, .txt, .pdf, ... and so on, and all I want to know are the .dat files, I use the following command:

Code:

cat "list.txt" | grep .dat

however, I know want to do the opposite, that is specify the extension that I do not want - that is to say that I want all extension types except for .dat...
what paramater must I specify in grep that will allow me to do this?

bigrigdriver · 07-03-2011, 05:49 PM

See the grep man page. There is an option ( -v ) which inverts the match (match all except the given pattern).

Code:

cat "list.txt" | grep  -v .dat

j1alu · 07-03-2011, 08:31 PM

You don't need to use `cat`:

Code:

grep pattern file

the dot needs to be escaped, else you match any single character with a dot
(if you escape it you match a dot literally):

Code:

grep  -v '\.dat' list.txt