Overview
supuner (SUPpress UNless ERror) executes a command and manipulates its stderr and stdout, allowing the user control over when they are displayed and / or outputted. It has two chief uses:
- Suppressing all output from a command unless there is an error, in which case the combined output of stderr and stdout is sent to stderr. This is useful for `chatty' scripts in cron jobs: if they run successfully, receiving an e-mail from them is distracting.
- Allowing long-running processes (e.g. database processing jobs) to run inside a
screen/tmux, sending output to both the console and a log-file. If an error occurs, the log file can then be e-mailed to an appropriate person.
Download
- supuner 0.1 (2011/06/19) (4Kb)
- First public release.
supuner is part of my bin repository; you can track supuner's evolution via git.
Usage
The command-line arguments are as follows:supuner [-e] [-o <filename>] <command>Where:
-e | By default sunuper suppresses all output to stderr and stdout unless an error occurs in which case a combined copy of stderr and stdout is sent to stderr. With the -e (`echo') switch, the command's normal stdout and stderr are sent to the console. This allows one to both interactively view and log a commands output simultaneously. |
-o <filename> | is a file to store combined stderr / stdout output. Can be combined with -q if desired. |
<command> | is the program, plus arguments, for execution. |
supuner exits with the exit code of command.
Examples
Here are examples of the basic styles of use of supuner:
$ supuner ls /bin/sh $ supuner ls /bin/sh /doesntexist ls: /doesntexist: No such file or directory /bin/sh $ supuner -e ls /bin/sh /bin/sh $ echo $? 0 $ supuner -e ls /bin/sh /doesntexist ls: /doesntexist: No such file or directory /bin/sh $ echo $? 1 $ supuner -o /tmp/o -e ls /bin/sh /doesntexist ls: /doesntexist: No such file or directory /bin/sh $ cat /tmp/o ls: /doesntexist: No such file or directory /bin/sh $Taking this, we can then do some more useful things. For example, we can run a command, see its output in the console, and log that to a file; if the command fails, we can then e-mail the relevant person with the copy of the log:
$ supuner -o /tmp/o -e ls /bin/sh /doesntexist || mail -s "Error from ls" somebody@something.com < /tmp/o ls: /doesntexist: No such file or directory /bin/sh $If we want to do the same thing but without sending any output at all to the console we can do the following:
$ supuner -o /tmp/o ls /bin/sh /doesntexist >2 /dev/null || mail -s "Error from ls" somebody@something.com < /tmp/o $