Nohup: Redirect stderr to file and dismiss stdout

Question

Per default, nohup writes stdout to nohup.out and dismisses stderr. I would like to have it the other way around:

write stderr to a file and dismiss stdout.

Answer 1

You can do it like this:

nohup command 2>&1 >/dev/null &

Because the first redirect is from STDERR to current handler of STDOUT it write to nohup.out. Then STDOUT is redirected to NULL

Answer 2

Just redirect standard error to the file you want:

$ ls
test.sh
$ cat test.sh
#!/bin/bash
echo "out"
echo "error" 1>&2
$ ./test.sh
out
error
$ nohup ./test.sh < /dev/null > /dev/null 2> err.out
$ ls
err.out  test.sh
$ cat err.out
error

From the manual:

If standard input is a terminal, redirect it from an unreadable file. If standard output is a terminal, append output to nohup.out if possible, $HOME/nohup.out otherwise. If standard error is a terminal, redirect it to standard output. To save output to FILE, use nohup COMMAND > FILE.

Given that it is silent if stderr is redirected, it stands to reason that it would behave normally, and, as shown above, it does.