(Bash) Redirect all output from script to all.log and copy of errors to err.log

hmsdefender · 03-04-2010, 02:44 PM

For simplicity assume the following script "hi.sh"

#!/bin/sh
#
echo hi
ehco hi
echo hi

Executing hi.sh produces the following on the screen ...

hi
./hi.sh: line 4: ehco: command not found
hi

I want to save the combined output (stdout & stderr) to a file called all.log, but also save stderr to a file called err.log. I've tried several methods using snippets regarding redirecting i/o from numerous forums and texts, but have been unsuccessful.

I tried calling hi.sh from another script (this is more like what I am doing for real) to see what results I get. Assuming the following script called callit.sh

#!/bin/sh
#
((hi.sh 3>1& 1>&2 2>&3) | tee /dev/tty) > err.log

Executing callit.sh I get the following output...

hi
./hi.sh: line 4: ehco: command not found
hi

However, if I use "callit.sh > all.log" I get the following output...

hi
hi
./hi.sh: line 4: ehco: command not found

In both cases err.log contains ...

./hi.sh: line 4: ehco: command not found

The file all.log is empty. I've tried many variations of the call within callit.sh and using redirect outside of callit.sh. The best I can get is err.log with...

./hi.sh: line 4: ehco: command not found

and all.log with ...

hi
hi
./hi.sh: line 4: ehco: command not found

As you can see in the later, the error message is out of sequence with the rest of the output due to subshell issues. Not an problem with a small example, but is the contents of all.log is useless if there are thousands of lines of content, but the errors are bunch at the end.

Any ideas? (be kind)

Ron

blacky_5251 · 03-04-2010, 06:14 PM

Excellent question. Try this:-

Code:

hi.sh > >(tee -a all.log > /dev/null) 2> >(tee -a all.log err.log > /dev/null)

Have fun coming to grips with the command line !!!

grail · 03-04-2010, 09:01 PM

This worked for me:

Code:

 ./hi.sh 2>&1 1> all.log 2> err.log

My bad blacky ... I too have your output (should look at it all before I post next time :$

blacky_5251 · 03-05-2010, 12:36 AM

I don't see how it could. Can you post the log files? When I do that, this is what I get:-

Code:

[irb@eddie bin]$ ./hi.sh 2>&1 1> all.log 2> err.log
[irb@eddie bin]$ more *.log
::::::::::::::
all.log
::::::::::::::
hi
hi
::::::::::::::
err.log
::::::::::::::
./hi.sh: line 4: ehco: command not found
[irb@eddie bin]$

The first redirection (2>&1) redirects stderr to stdout, which at that point in the process is still going to the screen. Then you redirect stdout to all.log, which means the non-error statements (2 x echo) send their output to all.log, but it has no impact on the first redirection you made (i.e. stderr is still going to the screen). Then stderr is redirected (again) to err.log. So your command can be rewritten as:-

Code:

./hi.sh 1> all.log 2> err.log

If this is in fact working for you (which it shouldn't be), which distro and shell are you using?

bigearsbilly · 03-05-2010, 08:04 AM

you can put it at the top of the script, (sh type shells only) thus:

Code:

#!/bin/sh
exec 2> err.log
exec >  out.log
...
...
...

blacky_5251 · 03-05-2010, 01:52 PM

Does that get stderr into the same log file (all.log) as stdout though? I would have thought that just puts stderr in one file and stdout in another.

The OP's need to have stderr and stdout combined contemporaneously in one file, plus stderr in another file, means this is something that "standard" redirection can't do.