source: vendor/bash/3.1-p17/examples/functions/lowercase

#! /bin/bash
#
# original from
# @(#) lowercase.ksh 1.0 92/10/08
# 92/10/08 john h. dubois iii (john@armory.com)
#
# conversion to bash v2 syntax done by Chet Ramey

lowercase()
{
        for file; do
                [ -f "$file" ] || continue
                filename=${file##*/}
                case "$file" in
                */*)    dirname=${file%/*} ;;
                *) dirname=.;;
                esac
                nf=$(echo $filename | tr A-Z a-z)
                newname="${dirname}/${nf}"
                if [ "$nf" != "$filename" ]; then
                        mv "$file" "$newname"
                        echo "lowercase: $file -> $newname"
                else
                        echo "lowercase: $file not changed."
                fi
        done
}