I have the following command:
find / -name libGL.so.1
Which returns lots of lines with "Permission denied". I want to exclude such lines, so I added the following:
find / -name libGL.so.1 | grep -v 'denied'
But the output is the same - my grep -v 'denied' is not filtering out the lines with Permission denied. I've tried many variations, looked over grep tutorials, but I cannot figure out the problem. Any suggestions?
That's nothing to do with grep - it's because the pipe | redirects the standard output stream stdout whereas the Permission denied messages are in the standard error stream stderr. You could achieve the result you want by combining the streams using 2>&1 (redirect the stream whose file descriptor is 2 to the stream whose file descriptor is 1) so that stderr as well as stdout gets piped to the input of the grep command
find / -name libGL.so.1 2>&1 | grep -v 'denied'
but it would be more usual to simply discard stderr altogether by redirecting it to /dev/null
find / -name libGL.so.1 2>/dev/null
If you take a look at the Bash man page you'll likely notice this blurb:
If
|&is used, the standard error of command is connected to command2's standard input through the pipe; it is shorthand for2>&1 |.
So you can also use this construct as well if you want to join STDERR and STDOUT:
find / -name libGL.so.1 |& grep -v 'denied'
/foo/bar/denied/libGL.so.1, combining stdout and stderr then filtering would hide the result
Your command should be:
find / -name libGL.so.1 2>/dev/null
Find is complaining about permissions on standard error (fd2). In order to eliminate those lines, redirect (>) standard out to the bit bucket (/dev/null).
The "permission denied" lines are going to the stderr (standard error) stream, but you are piping stdout (standard out) through grep.
You can redirect away stderr entirely with
find / -name libGL.so.1 2> /dev/null
Have you tried calling the command with sudo?
sudo find / -name libGL.so.1
If it still shows the message, use the already mentioned redirect of stderr (fd=2) to nirvana (/dev/null):
sudo find / -name libGL.so.1 2> /dev/null
More ideas here, good luck!
