Customize help output from optparse (or argparse)

[Thomas 'PointedEars' Lahn]

Thorsten Kampe wrote:

> I'm using optparse for a little Python script.
> 
> 1. The output from "--help" is:
> """
> Usage: script.py <arg>
> 
> script.py does something
> 
> Options:
>   -h, --help   show this help message and exit
> """
> 
> I would prefer to have the description before the usage, like...
> """
> script.py does something
> 
> Usage: script.py <arg>
> 
> Options:
>   -h, --help   show this help message and exit
> """
> 
> 2. The output from "--doesnotexit" is:
> """
> Usage: script.py <arg>
> 
> script.py: error: no such option: --doesnotexist
> """
> 
> I would prefer to have the error first, then the usage and additionally
> the options, like...
> """
> script.py: error: no such option: --doesnotexist
> 
> Usage: script.py <arg>
> 
> Options:
>   -h, --help   show this help message and exit
> """
> 
> Is that possible with either optparse or the "new kid on the block"
> argparse. If so how?

You can easily have #1 with optparse.OptionParser(usage="…")¹, but optparse 
is deprecated in favor of argparse.ArgumentParser.  I do not think you can 
have #2 with either optparse or argparse: OptionParser() would print the 
error message last, and ArgumentParser() would not print the description
on error.  Subclassing ArgumentParser might be feasible, though.

______
¹  <http://PointedEars.de/devel/tools/text/odfinfo/>
-- 
PointedEars

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