#/usr/bin/perl

die "Usage: fixscripts [files]\n" unless @ARGV;

# Configuration parameters.

$BIN = '/usr/local/bin';
$SCRIPTS = '/u/scripts';
$BAK = 'bak';

# Process each file.

foreach $file (@ARGV) {
    unless (-T $file) {
	warn "Can't process binary file: $file\n";
	next;
    }
    open(FILE, $file)
	|| do { warn "Can't open $file: $!\n"; next; };

    # Now process the file.

    $contents = '';
    $changed = 0;
    while (<FILE>) {
	if (m#$BIN#o) {
	    print STDERR "<$file:\t",$_;
	    $changed++;

	    if (m#:/#o) {                       # a $path
		s#$BIN#$BIN:$SCRIPTS#o;
	    }
	    elsif (m# /usr# && /set\s/) {       # a $PATH
		s#$BIN([^/])#$BIN $SCRIPTS$1#o;
	    }
	    else {

		# Try substitutions until one works.

		    s#$BIN/(\w+)#
		      -f "$SCRIPTS/$1" ?
		      "$SCRIPTS/$1" :
		      "$BIN/$1"#oeg             # a program
		||
		    s# $BIN# $BIN $SCRIPTS#o    # $PATH?
		||
		    s#$BIN #$BIN $SCRIPTS #o    # $PATH?
		||
		    s#:$BIN#:$BIN:$SCRIPTS#o    # $path?
		||
		    s#$BIN:#$BIN:$SCRIPTS:#o    # $path?
		;
	    }
	    print STDERR ">$file:\t",$_;
	}
	$contents .= $_;
    }
    close FILE;

    if ($changed) {
	rename($file,"$file.$BAK") ||
	      do { warn "Can't rename $file: $!\n"; next; };
	open(FILE, ">$file") ||
	      do { warn "Can't make $file: $!\n"; next; };
	print FILE $contents;
	close FILE;
    }
}