Question

The command

grep shutting log.log

returns nothing.

My script is as follows

#!/bin/bash
FAIL=`grep shutting log.log`
if [ "$FAIL"="Binary file log.log matches"  ]; then
    echo FOUND
else
    echo NOT FOUND
fi

I’m expecting NOT FOUND but get FOUND

Answer 1

You have to put spaces around the = operator in an [ ... ] expression; what you have written is being interpreted as [ string ], which tests whether string is nonempty.

But you don’t need backticks nor string comparison at all here. Try this instead:

if grep -q shutting log.log
then echo FOUND
else echo NOT FOUND
fi

(Thankfully, the systems that did not have the -q option to grep have long since gone to the great bit bucket in the sky.)