Shell – stdout and stderr redirection to different files

command lineio-redirectionshellstderrstdout

How can I redirect stdout to 2 different files and stderr to another, different file?

I want something like <my_cmd> 1> file1 file2 2>file3

I know:
<my_cmd> | tee file1 file2 > /dev/null

would redirect stdout to file1 and file2.
But I also want stderr to be redirected to a different file. How can I achieve this?

Best Answer

This should do:

<my_cmd> 2>file3 | tee file1 file2 > /dev/null

The stderr redirection is done first and then tee gets just stdout.

Related Solutions

Shell – Is it possible to create sticky redirection from stdout/stderr

exec 3>&1 4>&2 >log.txt 2>&1
echo hello
echo world
exec 1>&3 2>&4
less log.txt

I.e.: make file descriptors 3 and 4 copies of the current 1 (stdout) and 2 (stderr), redirect 1 to log.txt and 2 to the same as 1; then perform commands; then restore stdout and stderr from the saved values in file descriptors 3 and 4.

Shell – Replacing stdout with stderr

You can do it like this:

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

This redirects fd 2 to what fd 1 points to (i.e. stdout), then redirects fd 1 to /dev/null. The second redirect doesn't affect the first one, output to fd 2 will be sent to stdout.

Order does matter though. With this:

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

will send all output to /dev/null.

Best Answer

Related Solutions

Shell – Is it possible to create sticky redirection from stdout/stderr

Shell – Replacing stdout with stderr

Related Question