#!/usr/bin/perl -s

############################################################
# 			   rename
# 		Wed Nov 29 11:06:26 EST 1995
# 		       Meng Weng Wong
# 
# usage: rename function file ...
# flags: -i to confirm
#        -q to suppress "done" message.
#        -f to force even if target exists
# 
# typically, function will transform an old filename into
# a new filename.  eg, s/GIF/gif/
# 
# factoid 19990429 on #nop
# <newsham> if you have a fancy shell, there's probably a way to expand $f from .ext1 to .ext2 in one operation
# <newsham> ie.:  for f in *.ext1; do mv $f ${f%.ext1}.ext2; done
# <newsham> in bash
############################################################

if (! @ARGV) { 
    die "usage: rename transform-function file ...\n";
}

($function, @files) = @ARGV;

$renamed = 0;
$errors  = 0;

for (@files) {
    undef($to);
    eval "(\$to = \$_) =~ $function";
    if (defined($to)) {
	if ($to ne $_) {
	    if (-e $to) {
		print "rename: $to already exists.\n" unless ($f);
		next unless ($f || $i);
	    }
	    if ($i) {		# interactive
		print "rename: $_ -> $to [Yn] ";
		chop($input = <>);
		next if ($input !~ /^y|^$/i);
	    }		    
	    rename($_,$to);
	    $renamed++;
	}
    } else {
	print STDERR "error transforming $_\n";
	$errors++;
    }
}

$numfiles = @files;

if (! $q) {
    print STDERR "$renamed out of $numfiles renamed.";
    if ($errors) { print STDERR "  $errors errors."; }
    print STDERR "\n";
}