adding command line option -r

I want to add a command line option -r, recurse, to this code:

for name in *.$1; do
    stripped_name="$(basename "$name" ".$1")"
    mv "$name.$1" "$name.$2"
done

So if I enter "change -r txt doc", the command should be executed recursively on any subfolder. For example, if there is a file aaa.txt and a directory y containing files y/bbb.txt and y/ccc.txt....it should result in files aaa.doc, y/bbb.doc and y/ccc.doc.

Also if I don't supply the "-r", it 开发者_StackOverflowshould work as normal.

Does anyone know how to add this to my script?

I bet this is far from ideal, but how about the following? This uses find to get the files to rename, but if you don't supply the -r, it adds -maxdepth 1 to the arguments. Then it uses the rename(1) command on Debian based systems (e.g. Ubuntu) to rename the matching files. The -print0 and xargs -0 makes sure that this doesn't have problems with odd filenames that might contain newlines, etc.

#!/bin/bash

if [ x"$1" = x-r ]
then
    FIND_OPTIONS=""
    shift
else
    FIND_OPTIONS="-maxdepth 1"
fi

FROM="$1"
TO="$2"

find . $FIND_OPTIONS -name '*.'$FROM -print0 | xargs -0 rename "s/\.$FROM/\.$TO/"