How to silence output in a Bash script?

Question

If it outputs to stderr as well you'll want to silence that. You can do that by redirecting file descriptor 2:

# Send stdout to out.log, stderr to err.log
myprogram > out.log 2> err.log

# Send both stdout and stderr to out.log
myprogram &> out.log      # New bash syntax
myprogram > out.log 2>&1  # Older sh syntax

# Log output, hide errors.
myprogram > out.log 2> /dev/null

Redirect stderr to stdout

This will redirect the stderr (which is descriptor 2) to the file descriptor 1 which is the the stdout.

2>&1

Redirect stdout to File

Now when perform this you are redirecting the stdout to the file sample.s

myprogram > sample.s

Redirect stderr and stdout to File

Combining the two commands will result in redirecting both stderr and stdout to sample.s

myprogram > sample.s 2>&1

Redirect stderr and stdout to /dev/null

Redirect to /dev/null if you want to completely silent your application.

myprogram >/dev/null 2>&1

All output:

scriptname &>/dev/null

Portable:

scriptname >/dev/null 2>&1

Portable:

scriptname >/dev/null 2>/dev/null

For newer bash (no portable):

scriptname &>-

If you are still struggling to find an answer, specially if you produced a file for the output, and you prefer a clear alternative: echo "hi" | grep "use this hack to hide the oputut :) "

If you want STDOUT and STDERR both [everything], then the simplest way is:

#!/bin/bash
myprogram >& sample.s

then run it like ./script, and you will get no output to your terminal. :)

the ">&" means STDERR and STDOUT. the & also works the same way with a pipe: ./script |& sed that will send everything to sed