How to avoid messages from applications which I ran with a &?

Question

I ran dolphin like this:

dolphin . &

I see messages in the console like these:

QPixmap::scaled: Pixmap is a null pixmap

How can I keep the console clean or silent?

Answer 1

You can redirect the output to a file or to nowhere.

Using output redirection > you can redirect stdout and/or stderr away from the terminal.

To redirect stdout and stderr to a file use &> log.txt.

If you just want output to go way use &> /dev/null.

So you new command would be dolphin . &> /dev/null &

&> redirects all output

use > or 1> to redirect stdout only

use 2> to redirect stderr only

Note: if you want to append to a file rather than overwrite it use >> in place of >.

Answer 2

Redirect all the output into a black hole:

dolphin . > /dev/null 2>&1 &

The 2, 1 and 0 (not used here) stand for STDERR (where all the error messages are sent), STDOUT (where normal output goes) and STDIN (where the input) comes from. In a normal terminal STDOUT and STDERR are both printed to screen.

The above example redirects STDOUT with > to /dev/null and then redirects STDERR into STDOUT so both output streams end up at /dev/null.