Shell Programming and Scripting

Thanx Hugo and Jimbo. I think I will have to use and a.ascNEW approach here.

grep is what you are looking for.

First use ^$ to remove any blank lines, then grep -v to remove unique lines in the file. Then redirect to a new filename.


cat filename |grep -v ^$ |grep -v "unique header" |grep -v "unique footer" > new.filename

Remember the -v option for grep will remove/ignore lines and send the rest to standard out.

I think the one awk process is a far superior solution than four processes piped together.

Is superior, in all the ways. If somebody doubts it, use the time command.

yea, yea, yea...

I know that it wastes some amount of time and is firing off multiple processes...

I was going for simplicity. However, for single use items like removing blank lines grep -v ^$ is easy to remember.

I enjoy using awk as well, it is very cool. I am making my way through "The AWK Programming Language by Aho, Kerningan, Weinberger". Great book.

Thanks, Kelum_Magnus, for the awk book reference. To me, awk and vi were both very frustrating until I got the hang of them, now I love them.

And I definitely am not bashing grep. Every day you can see me using 4-5 piped greps.

But I strive for best practice. and I have improved my unix a huge amount, thanks to this forum and all the contributors, yourself included.