Shell scripting: Print output to logfile, error to logfile & screen

Lumberg · 04-17-2006, 02:56 PM

Wow, what a thorny problem.

I got as far as

(find /lcl/fst/ -name "*ooo*" >> log.txt) 2>&1 |(sed "s/^/STDERR:/" >> log.txt)

but there is some sort of race condition with the writing of STDERR and STDOUT which still will jumble the lines.

grrrrrr

jlliagre · 04-18-2006, 03:07 AM

Hey, reviving a 6 month old thread !

You can run the "script" command before running your find, and exit when it's done.

That way you'll have an ordered log of stdout and stdin in the typescript file.

Igorts · 05-21-2008, 04:30 AM

This thread is very old, yet I wanted to post the solution in case someone reads this:

Lets say you want to run "some_command", log its outputs (including stderr) and also output stderr to the screen:

Code:

((some_command 2>&1 1>&3 | tee /dev/stderr) 3>&1) > logfile

This is not perfect because it does not return a correct exit code (it always returns 0 - the exit code of 'tee').
So we improve this a little bit:

Code:

((some_command 2>&1 1>&3 | tee /dev/stderr ; exit ${PIPESTATUS[0]}) 3>&1) > logfile

In case "some_command" is stored in a variable such as $cmd, I would suggest adding "eval" so that quotes are handled correctly:

Code:

((eval $cmd 2>&1 1>&3 | tee /dev/stderr ; exit ${PIPESTATUS[0]}) 3>&1) > logfile

stefanlasiewski · 05-22-2008, 12:47 PM

Quote:

Originally Posted by Igorts

This is not perfect because it does not return a correct exit code (it always returns 0 - the exit code of 'tee').
So we improve this a little bit:

Code:

((some_command 2>&1 1>&3 | tee /dev/stderr ; exit ${PIPESTATUS[0]}) 3>&1) > logfile

Good solid example of Bash IO Redirection. Thanks!