#!/usr/bin/perl
use strict;

sub csv_split    {
    local $_ = shift || return undef;
    my @array = ();
    my $count = my $quoted = 0;
    while ( s/(.)// )    {
        my $char = $1;
        if ($char eq ',' && !$quoted) { $count++; next; }
        if ($char eq q/"/)    {
            unless ( $quoted && s/^\"// ) { $quoted = 1 - $quoted; nex
+t; }
        }
        $array[$count] .= $char;
    }
    return @array;
}

for my $line (<DATA>) {
    print "\nLine: $line";
    print "$_\n" for csv_split $line;
}

__DATA__
Simple cells,test,test
Cells with commas,"test 1a,1b","test, 2a 2b"
Cells with quotes,"test ""one""","""test"" two"
Quotes and commas,"test ""1a,1b""","""test 2a,""2b"
[download]

Sample of using undef and EDI element delimiter to control when to parse the meat of a transaction:

sub handle_edi    {
    my ($bank_name, $bu, $amt);
    local $/ = shift;
    open INFILE, shift;
    my $dlm = undef;
    while (<INFILE>)    {
        if ( /^ST(\W)820/ )    { $dlm = $1; }
        elsif ( $dlm && /^SE$dlm/ ) { undef $dlm; }
        elsif ( $dlm && /^BPR$dlm/ )    {
            my @sg=split "\\$dlm";
            $bank_name = $who{$sg[7]} || 'undefined';
            $amt = $sg[2];
            $amt =~ s/\.//g;
            $bu = &getbu ($sg[9]);
            $buhash{$bu}{bankname}=$bank_name if !defined $buhash{$bu}
+{bankname};
            $buhash{$bu}{count}{edi}++;
            $buhash{$bu}{$amt}{edi}++;
        }
    }
    close INFILE;
}
[download]

Template-to-HTML while avoiding existing HTML:

my %sc = qw ( \\* b / em _ u );
my %counts;
my %opened;

sub track  {
    $opened{$_} = 1 - ( $opened{$_} || 0 );
    return "<$sc{$_}>" if --$counts{$_} > 0 && $opened{$_};
    return "</$sc{$_}>" if ! $opened{$_};
    $_;
}

sub reg_fix  {
    my $line=shift;
    %counts = (); %opened = ();
    $line =~ s/<([^>]*<)/\&lt;$1/g; # Replace unmatched < with &lt;
    my @elems = split '(<.*?>)', $line;
    $line =~ s/<.*?>//g;
    $counts{$_} = @{[$line =~ m/$_/g]} for keys %sc;
    for my $elem ( grep !/^</, @elems )  { $elem =~ s#$_#&track#eg for
+ keys %sc; }
    join '',@elems;
}
[download]

Small YYYYMMDD date formater

$YYYYMMDD = 19000100+sprintf"%02d"x3,(localtime)[5,4,3];
[download]

Using same idea to get a hash of dates who's values are total file sizes from files last modified on those days.

find .|perl -lne'$t{19000100+sprintf"%02d"x3,(localtime((stat)[9]))[5,
+4,3]}+=-s if!-d}{print"$_ $t{$_}"for sort keys%t'
[download]

Universal ANSI X.12 data unwrapper:

#!/usr/bin/perl
while(1) {
    if (!$ARGV || /^IEA/)    {
        $/ = \1;
        1 while ($_ = <> || last) =~ /\s/;
        $/ = \104;
        die "Interchange can't start with $_" unless ($_ .= <>) =~ /^I
+SA[^\w\n]/;
        $/ = \(1 + y/\n//);
        $/ = substr( ($_ .= <>) , -1);
        die "Invalid terminator in $ARGV" if /\w$|\n.*\n$/ || ! s!\n|$
+/!!g;
    }
    else { last if !defined (($_ = <>) =~ s!\n|$/!!g); }
    print "$_\n";
}
[download]

Console Tic Tac Toe

$_="123
456
789
147,258,369,159,357";$p=X;sub d{/.{12}/s;print$&.$p;die$_ for@_}
n:d;$m=<>until$m=~/\d/&&s/$&/$p/g;/$p{3}/?d$p:!/\d/?d"Tie":$p=~y/XO/OX
+/;goto n
[download]