Question

i am trying to make this script that filters a line coming from ps..
the script it almost done, only this line missing.

for example,here’s a line i need to filter :

803 ?   (many spaces here)   00:00:00 atd

i need this like to look like this :

803 atd

i’ve tried everything but it seems that a simple sed argument can’t do this.. if sed detects something that has to be erased, it deletes the whole line after it..
please correct me if i am wrong and thanks for your time..

Answer 1

Try this command for sed:

sed 's/ .* / /'

It takes the first space, as much as possible, then the last space, and replaces them with a single space.

If you can have spaces at the beginning or the end of the string, then you need to be a little more careful with your sed command. It’s not nearly as elegant here:

sed 's/^ *\([^ ]\+\).*  *\([^ ]\+\) *$/\1 \2/'

This captures non-space characters and puts them in the output stream. Without an extended sed like GNU sed, you need to replace the occurrences of [^ ]\+ with [^ ][^ ]*.

That being said, awk is clearly the most graceful tool for this job.