UNIX for Dummies Questions & Answers

hi, I want to compare 2 files and see if there is a difference between them
so i did:
set aa = `diff file1.txt file2.txt`
if ($aa == "") then
echo "no difference"
else
echo "different files"
endif

and i get the error msg:
if: Badly formed number.



now when im doing the ccomperation like this:
set aa
if ($aa == "") then
echo "no difference"
else
echo "different files"
endif


it works good.
why the diff doing problams??
what can i do?

Well, you are using "if" incorrectly - it doesn't use parens.

But you don't to capture the output anyway. $? will be 0 if the files match, non-zero otherwise.

So

Code:

diff file1.txt file2.txt > /dev/null
if [ $? = 1  ] 
then echo "Nope"
else
echo "match"
fi

Code:

cmp -s

is more efficient than diff