Как перевести имя файла в нижний или верхний регистр

cat << END_SCRIPT > move-to-lower
#! /bin/sh
# rename files to lower/upper case...
#
# usage:
#    move-to-lower *
#    move-to-upper *
# or
#    move-to-lower -R .
#    move-to-upper -R .
#
 
help()
{
   cat << eof
Usage: $0 [-n] [-r] [-h] files...
 
-n      do nothing, only see what would be done
-R      recursive (use find)
-h      this message
files   files to remap to lower case
 
Examples:
       $0 -n *        (see if everything is ok, then...)
       $0 *
 
       $0 -R .
 
eof
}
 
apply_cmd='sh'
finder='echo "$@" | tr " " "\n"'
files_only=
 
while :
do
    case "$1" in
        -n) apply_cmd='cat' ;;
        -R) finder='find "$@" -type f';;
        -h) help ; exit 1 ;;
        *) break ;;
    esac
    shift
done
 
if [ -z "$1" ]; then
    echo Usage: $0 [-h] [-n] [-r] files...
    exit 1
fi
 
LOWER='abcdefghijklmnopqrstuvwxyz'
UPPER='ABCDEFGHIJKLMNOPQRSTUVWXYZ'
 
case `basename $0` in
    *upper*) TO=$UPPER; FROM=$LOWER ;;
    *)       FROM=$UPPER; TO=$LOWER ;;
esac
 
eval $finder | sed -n '
 
# remove all trailing slashes
s/\/*$//
 
# add ./ if there is no path, only a filename
/\//! s/^/.\//
 
# save path+filename
h
 
# remove path
s/.*\///
 
# do conversion only on filename
y/'$FROM'/'$TO'/
 
# now line contains original path+file, while
# hold space contains the new filename
x
 
# add converted file name to line, which now contains
# path/file-name\nconverted-file-name
G
 
# check if converted file name is equal to original file name,
# if it is, do not print nothing
/^.*\/\(.*\)\n\1/b
 
# now, transform path/fromfile\n, into
 
# now, transform path/fromfile\n, into
# mv path/fromfile path/tofile and print it
s/^\(.*\/\)\(.*\)\n\(.*\)$/mv \1\2 \1\3/p
 
' | $apply_cmd
END_SCRIPT

$ ln -s move-to-lower move-to-upper
$ chmod +x move-to-lower move-to-upper