Question

I have 2 big files and I want to make a diff between the top lines of each files, but i don’t want to use intermediate files. I would like to do something like that :

diff `head -n 2000 file1.log` `head -n 2000 file2.log`

I remember I’ve done something like that a long time ago, ie. make a command like head -n 2000 file1.log interpreted as a file. But I don’t remember how. Maybe it was another shell…
Thank you.

Answer 1

You’re probably thinking of process substitution in bash. For example, try:

 diff <(head -n 2000 file1.log) <(head -n 2000 file2.log)