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Shell Programming and Scripting

Append stderr

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# 1  
Old 05-18-2010
Append stderr
Hi everybody.

I was used to redirect stderr to a file in this way, calling a generic script:
Code:
./myScript &> output.log

But now I need something more sophisticated...Inside a bash script I launch an executable in this way:
Code:
${command}  >> "${globalLogFile}"

So I redirect the stdout into globalLogFile.
How to contemporary redirect the stderr to another log file, APPENDING it?

Thanks in advance!
# 2  
Old 05-18-2010
Something like:

Code:
${command}  >> "${globalLogFile}" 2>> $globalErrFile

# 3  
Old 05-18-2010
Ok, thanks, pretty simple...

And is it possible to give the stderr as input to a fuction?

For example, I have this function:
Code:
log() {
    echo "$(date) - $1" >> "output.log"
}

Is it possible to do something like (pseudocode):
Code:
${command}  >> "${globalLogFile}" 2>> log "&2"

or something?

---------- Post updated at 08:36 AM ---------- Previous update was at 05:01 AM ----------

No ideas?

Moderator's Comments:
Mod Comment Do not bump posts - THANK YOU.
Last edited by Scott; 05-20-2010 at 05:23 AM..
# 4  
Old 05-18-2010
time zones are funny things, aren't they...?

Code:
-> ls -ltr nowhere.txt 2>&1 |tee -a /tmp/error_test.log
nowhere.txt: No such file or directory

-> cat -n /tmp/error_test.log                          
     1  nowhere.txt: No such file or directory
     2  nowhere.txt: No such file or directory

# 5  
Old 05-18-2010
Excuse me, but I do not understand your answer...No ideas for the stderr/log stuff?
# 6  
Old 05-18-2010
This is a forum more than a chat, so patience is sometimes needed before you get a response.

Meanwhile, you can capture your STDERR into your STDOUT using something like my sample, or using your own sample:
Code:
$(command) 2>&1 |tee -a [log.file]

This will allow your error to echo to screen, while it also appends to the named file.
# 7  
Old 05-18-2010
Hi.

Here's an example, of what I think you are asking.
Code:
$ cat LogTest
LogError() {
  while read LINE; do
    echo "ERROR:  $LINE"
  done
}

PrintSomething() {
  echo "OK"
  echo "ERROR1" >&2
  echo "ERROR2" >&2
}

PrintSomething 2>&1 > some_log_file.txt | LogError


$ ./LogTest
ERROR:  ERROR1
ERROR:  ERROR2


$ cat some_log_file.txt
OK

Errors go through function LogError - and from there you can do with it what you wish.
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