Change Extensions

change-extension.sh

#!/bin/sh
# Search recursively for all files with the extension of the first argument.
# Replace them with the extension of the second argument.

if [ "$#" -ne 2 ]; then
    echo "Usage:"
    echo "    $0 <from> <to>"
    exit 1
fi

FROM=$1
TO=$2

read -r -p "Convert all *.${FROM} to *.${TO}? [y/N] " input

case "${input}" in
    [yY])
        for f in $(find . -name "*.${FROM}"); do
            mv --verbose -- "$f" "${f%.${FROM}}.${TO}"
        done
        ;;
    [nN])
        exit 0
        ;;
    *)
        echo "Invalid option: ${input}"
        exit 1
        ;;
esac