How can I hide the screen output (printf) of a shell application in Linux?
You can redirect the output of any program so that it won't be seen.
$ program > /dev/null
This will redirect the standard output - you'll still see any errors
$ program &> /dev/null
This will redirect all output, including errors.
The first one didn't work for wget Jul 17, 2009 at 3:07
That's cause wget uses stderr for some of it's output. The second one should work. Jul 17, 2009 at 3:08
2Incidentally, you might want to save that wget output to a log file, so when/if your download stops working, you can figure out why. If it's in a script anyway. If this is a one-off type run, then yea, to the trash Jul 17, 2009 at 3:17
wgetyou can use the
-qoptions to make it quiet.– pkhamreMar 30, 2012 at 10:12
Any way to suppress output written directly to /dev/tty?– d11wtqJul 17, 2014 at 7:08
There are three I/O devices available on the command line.
standard input - 0 standard output - 1 standard error - 2
To redirect standard output (the default output) to a file (and overwrite the file), use
command > file.log
To append to file.log, use two
command >> file.log
To redirect standard error to the file.log, use
command 2> file.log
And to append
command 2>> file.log
To combine the outputs into one stream and send them all to one place
command > file.log 2>&1
This sends 2 (standard error) into 1 (standard output), and sends standard output to file.log
Notice that it's also possible to redirect standard input into a command that expects standard input
command << file.txt
For more details, check out the Advanced Bash Scripting Guide.
Can somebody explain how the
command > file.log 2>&1works? May 23, 2011 at 22:37
How low of a level would you like to know? May 29, 2011 at 13:54
4@nomoreink: it's actually 2 commands, one is
> fileand the second one is
2>&1. The first one redirects the standard out to a file. The second one takes 2nd file descriptor and redirects it to first one. You can do the reverse, redirect standard output to standard error using
>&2and then redirect standard error to a file with
2> file. Nov 27, 2012 at 11:39
Hide standard output:
Hide standard and error outputs:
./command >/dev/null 2>&1
Hide standard output and error outputs and release the terminal (run the command in the background):
./command >/dev/null 2>&1 &
If you just want to hide the output (and not save it to a file), you can use:
$ command &> /dev/null
This will redirect the output to a file called null Jul 17, 2009 at 3:03
It generated a null file Jul 17, 2009 at 3:04
1you wouldn't have meant /dev/null, would you?– BabuJul 17, 2009 at 3:09
1Yes, I would have, Babu. I meant $ command &> /dev/null. My apologies for typing too fast for my own good.– LuchoJul 17, 2009 at 3:13
For Mac OS X v10.6 (Snow Leopard):
If you need to hide the output without letting the program know it by checking the output/error file descriptor, you can try using the following in a shell:
stty flusho; command ;stty -flusho
or if you just want to hide input from the terminal by the way:
stty -echo; command ;stty echo
See stty(1) manual page for more information.
For Linux, all I know is that Ubuntu 10.04 (Lucid Lynx) and some Debian/Arch Linux (commented below - thanks, hendry) doesn't have the
flusho setting (and I can't see anything other appropriate in the man-page). The
echo setting works on the Ubuntu anyway.