Question

I am writing a custom apache log parser for my company and I noticed a performance issue that I can’t explain. I have a text file log.txt with size 1.2GB.

The command: sort log.txt is up to 3 sec slower than the command: cat log.txt | sort

Does anybody know why this is happening?

Answer 1

cat file | sort is a Useless Use of Cat.

The purpose of cat is to concatenate
(or “catenate”) files. If it’s only
one file, concatenating it with
nothing at all is a waste of time, and
costs you a process.

It shouldn’t take longer. Are you sure your timings are right?

Please post the output of:

time sort file

and

time cat file | sort

You need to run the commands a few times and get the average.