I'm sure this kind of script has been written a million times. I had a need for it (mc-find-hosts was wearing on my will to live), so I wrote another one.
It's a translator for command line arguments. You can configure it to transform anything into anything, as long as you know the Python regular expressions syntax.
gimmer looks in /etc/gimmer and ~/.gimmer for files to import patterns from. It evals every line in the file, assuming that it will result in a dictionary if {}'s are added to the ends. It then runs every command line argument through the list of patterns until one applies. If none apply, it passes the argument along as is.
GIMMER_BINARYdetermines what binary the script execs
It runs execv on the binary it's configured to use with the resulting list of arguments.
The default binary is mc-find-hosts, because that's what I fucking needed it
for. It can be overriden (see Environemnt Varibles).
Some sample patterns are found in .gimmer.sample For example,
"^(i\-\w+)$": "-Fec2_instance_id=\g<1>"
will recognize any argument that looks like an instance ID (i-23adf34) and turn
it into -Fec2_instance_id=i23adf34 and the resulting mc-find-hosts command
will find that instance.