Perl Code for cktb.pl

This is the perl program code for cktb.pl. It looks for blanks or tabs at the end of lines and prints a report of what it finds. This has been updated to use lexical file handles and to print its output using print and printf rather than Perl formats.

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#!/usr/bin/env perl
# Look for and count the blanks or tabs at the end of lines
# --Kent Nassen, 5/26/99, 6/11/99, 6/28/00, 9/20/25

# 6/28/00: only print longest string of whitespace message if the file
# had trailing whitespace.  Added run_time to header.

# 9/20/25: Removed Perl formats. Use print and printf instead. This means
# pagination is done manually and page 1 is handled separately because
# there are no lines read at that point. Use lexical filehandles and
# remove the use of the FileHandle module. Use our() for variables now. 

#use warnings;
#use strict;
use Getopt::Std;

our ($file, $filename, $input, $line, $len, $whitespace, $match,
  $matchcount, $ProgName, $version, $pagesize, $longest, $longline, $opt_l,
  $run_time, $trail, $pagenum, $linecount);

$pagesize=54;

#$version="v1.1, 6/11/99";
$version="v1.2, 9/20/25"; # p;rint titles on all pages
$run_time=localtime(time);

($ProgName = $0) =~ s%.*/%%; # Unix
#($ProgName = lc $0) =~ s%.*\\%%;  # DOS

die "\n*** $ProgName: need a filename to test. \n\
$ProgName: Find lines with trailing white space (tabs or spaces) in files,\
      by Kent Nassen, $version\n\
     Usage: $ProgName [-l] filename [filename...]\
            where -l gives long output, instead of a summary.\n\n"
        unless defined($file=$ARGV[0]);

getopts('l');

sub print_banner {
     my ($pagenum) = @_;
     print "\n Page $pagenum\n\n"; 
     print "   $ProgName: Find lines with trailing spaces or tabs,",
         " by Kent Nassen, $version\n", 
         "   Scanning for trailing white space in the file: $file\n",  
         "   Report generated: $run_time\n\n";
     print "\n                    Trailing WS\n";
     print "    Line #            Length\n";
     print "    -------         -----------\n"; 
}

# Check a file for trailing blanks/white space
my $fh;
foreach $file (@ARGV) {
     $pagenum=1;
     # Print Page 1 page number, titles, and table headers for opt_l case.
     if ($pagenum==1) { print " \nPage 1\n\n"; }
     print "   $ProgName: Find lines with trailing spaces or tabs,",
         " by Kent Nassen, $version\n", 
         "   Scanning for trailing white space in the file: $file\n",  
         "   Report generated: $run_time\n\n";
     if ( $opt_l ) {
     print "                    Trailing WS\n";
     print "    Line #            Length\n";
     print "    -------         -----------\n"; 
     }
    process($file, $fh, \$pagenum);
}

sub process {
    $match="";
    $- = 0;
    $pagenum=2;
    my ($file, $fh, $pagenum_ref) = @_;
    $pagenum = defined $pagenum_ref ? $$pagenum_ref : 1;
    $filename=$file;
    $line=$matchcount=$longest=$longline=$linecount=0;
    $input++;
    unless (open $fh, $filename) {
        print STDERR "\n  $ProgName: *** Can't open $filename: $!\n\n";
        return;
    }
    while (<$fh>) {
        chomp;
        $line++;

        if (/([\t\s]+)$/) {
            $$pagenum_ref = $pagenum if defined $pagenum_ref;
            $match=$_; # keep full line on a match
            $trail=$1; # the white space;
            $linecount++;
            $matchcount++;
            $len=length($trail);
            if ($len>$longest) {
                $longest=$len; 
                $longline=$line;
            }
            if ($opt_l) {
                if ($linecount % 45 == 0) {
                     print_banner($pagenum);
                     $pagenum++;
                     $$pagenum_ref = $pagenum if defined $pagenum_ref && ref($pagenum_ref) eq 'SCALAR';
                }
                # opt_l case: print the table data
                printf "      %5d       %7d\n",$line,length($trail);
            }
        }
    } # end of while()
    if (!$matchcount) {
        print "\n   *** No lines found with trailing white space";
        $longest=0;
        $longline=$line;
    }
    print "\n   $line total lines in the file '$file'.\n";
    if ($matchcount) {
        print "   Longest string of trailing whitespace was $longest",
                " characters at line $longline.\n\n",
    "------------------------------------------------------------------------\n";
    }
    $longest=$longline=0;
    close $fh;
}

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Last-modified: Sat Sep 20 23:34:14 EDT 2025