topic Re: Remove errors at command line in Operating System - HP-UX

Remove errors at command line

Vanquish — Tue, 20 Apr 2004 11:31:17 GMT

i am doing a diff between 2 files if the file does not exists it gives error message on command line i want to remove it
diff: No such file or directory
Thanks

Re: Remove errors at command line

Marvin Strong — Tue, 20 Apr 2004 11:34:40 GMT

add 2>/dev/null to the end of your diff command.

example

diff file1 file2 2>/dev/null

Re: Remove errors at command line

Juergen Tappe — Tue, 20 Apr 2004 11:34:45 GMT

Easy answer :
diff file1 file2 2>/dev/null

and the error messages going to "trashcan".

Juergen

Re: Remove errors at command line

A. Clay Stephenson — Tue, 20 Apr 2004 11:34:48 GMT

That error message goers to stderr (like good UNIX programs should) while the normal output goes to stdout. The solution is simple:

diff file1 file2 2>/dev/null

Re: Remove errors at command line

Hazem Mahmoud_3 — Tue, 20 Apr 2004 11:37:45 GMT

# diff file1 file2 2 > /dev/null

-Hazem

Re: Remove errors at command line

A. Clay Stephenson — Tue, 20 Apr 2004 11:52:33 GMT

I should add that there is a danger to ignoring the error message. It now is not possible to distinguish between two files which match exactly (ie no diff) and a missing file. Both cases will result in no output to stdout. You need to now check the status of the diff command as well as examine stdout. Diff will return a non-zero exit status on failure.

e.g.
diff file1 file2 2>/dev/null > difffile
STAT=${?}
if [[ ${STAT} -ne 0 ]]
then
echo "Diff failed. Status = ${STAT}"
fi

Re: Remove errors at command line

Rory R Hammond — Wed, 21 Apr 2004 10:48:58 GMT

From a Shell Script:

if
[ -f file1 -a -f file2 ]
then
diff file1 file2
fi

Suggest if you want from a command line:
1. make a function in .profile

difff()
{
if
[ -f $1 -a -f $2 ]
then
diff $1 $2
fi
}

2. command line
difff file1 file2