:
##########################################################################
# Title      :	rename - rename files (change extension)
# Author     :	Heiner Steven <heiner.steven@odn.de>
# Date       :	1995-05-18
# Requires   :	
# Category   :	File Utilities
# SCCS-Id.   :	@(#) rename	1.2 03/12/19
##########################################################################
# Description
#
##########################################################################

PN=`basename "$0"`			# program name
VER='1.2'

usage () {
    echo >&2 "$PN - rename files: change extension, $VER (stv '95)
usage: $PN [-f] [oldext [newext [files ...]]]
    -f:		force rename, do not prompt for confirmation
    oldext	old file extension
    newext	new file extension

Both extensions must not contain wildcards. Missing parameters are
prompted for. The old file extension is 'anchored' to the end of the
line, so 'old' will match *old.

Example:	$PN \\.old \\.new *.old"
    exit 1
}

msg () {
    for msgLine
    do echo "$PN: $msgLine" >&2
    done
}

fatal () { msg "$@"; exit 1; }

Interactive=yes				# yes/no
while [ $# -gt 0 ]
do
    case "$1" in
	--)	shift; break;;
	-f)	Interactive=no;;
	-h)	usage;;
	-*)	usage;;
	*)	break;;			# First file name
    esac
    shift
done

if [ $# -gt 0 ]
then Old="$1"; shift
else echo -n "old extension (e.g. '.old'): " >&2
     read Old || exit 2
fi
case "$Old" in
    "")	    exit 0;;
    *\**)   fatal "no regular expressions allowed: $Old";;
esac

if [ $# -gt 0 ]
then New="$1"; shift
else echo -n "new extension (e.g. '.new'): " >&2
     read New || exit 2
fi
case "$New" in
    "")	    exit 0;;
    *\**)   fatal "no regular expressions allowed: $New";;
esac

if [ $# -eq 0 ]
then echo -n "files to rename: *" >&2
     read Files || exit 2
     set -- ${Files:-*}
fi

[ -z "$Old" -o -z "$New" ] && usage

# Play around with a status indicator...
i=0 p0="|" p1="/" p2="-" p3="\\"

n=0				# Number of files renamed

trap "[ \$n -gt 0 ] && echo \"$PN: \$n file(s) renamed\"" 0
trap "exit 2" 1 2 3 15

for File
do
    eval p=\$p$i
    echo -n "$p" >&2
    i=`expr \( $i + 1 \) % 4`

    [ -f "$File" ] || {
	msg "$File is no file - ignored"
	continue
    }
    Name=`echo "$File" | sed -e "s/$Old$/$New/"`
    [ -n "$Name" -a "$Name" != "$File" ] && {
	[ $Interactive = yes ] && {
	    echo -n "$PN: rename <$File> to <$Name> (y/n)? y" >&2
	    read ok || exit 2
	    case "$ok" in
		[yYjJ]*|"")	;;	# rename
		*)	continue;;
	    esac
	    msg "$File	-> $Name"
	}
	mv "$File" "$Name" && n=`expr ${n:-0} + 1`
    }
done
exit 0