How can I hide the output of a shell application in Linux?

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.

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 >s

 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.

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