[ILUG] Logging hack wanted

Kenn Humborg kenn at bluetree.ie
Thu Jan 27 13:29:23 GMT 2000


> The only way I can figure to pipe stderr to another command is
> 
> $ cmd > /dev/null 2> /dev/tty1 | another_cmd

... and that won't work when you're on a different terminal,
or when you don't even have a terminal.

> 
> I'm sure there must be an easier way? But I couldn't anything like just
> 
> $ cmd 2> | another_cmd
> 
> to work.

OK then, _I'll_ read the docs for you.  Pay attention:

$ cmd 2>&1 1>/dev/null | another-cmd

According to the bash man page, 2>&1 says "make fd 2
a duplicate of fd 1".  Note that this is a 'deep copy',
i.e. subsequently modifying fd 1 will have no effect on 
fd2.  So fd 2 (stderr) now writes to the same place
as fd 1 (stdout).

1>/dev/null means "open /dev/null for write on fd 1".
So stdout now writes to the bitbucket.

The original poster wanted to date stamp and log the 
stuff coming from 'cmd'.  Try using the logger command:

$ cmd 2>&1 1>/dev/null | logger -p local1.info

and configure syslog to write local1.info to /var/log/whatever.

Later,
Kenn






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