[SOLVED] diff

Markus72 · 03-27-2011, 03:55 AM

Hi,

I'm sorry for this basic question. I can't for the life of me remember how to do it and no lack of Google searches has found me an answer.

I simply wish to compare 2 files using diff and perform an action if they are different (e.g. move the file that's different).

I'm using:-

diff -q file01 file02

and get:-

Files file01 and file02 differ

Does the diff -q produce some kind of standard out that I can use in a simple if statement, such as:-

if [ diff -q file01 file02 ] then
echo Files different
else
echo Files same
fi

I did actually try that, but of course didn't work

. Once again sorry for the simple question, I'm expecting to kick myself once I find out how it's done

.

Cheers,

KISA

druuna · 03-27-2011, 04:05 AM

Hi,

The exit status (0 for not different, 1 for different) of the diff command can be used.

Code:

#!/bin/bash

diff -q file1 file2 1>/dev/null
if [[ $? == "0" ]]
then
  echo "The same"
else
  echo "Not the same"
fi

I added the 1>/dev/null to suppress all the output, which is probably not needed.

Hope this helps.

Markus72 · 03-27-2011, 04:11 AM

Thanks for the quick reply druuna, that's exactly what I was after.

Cheers.

druuna · 03-27-2011, 04:13 AM

You're welcome

BTW: Can you put up the [SOLVED] tag (first post -> Thread Tools).