256colors.pl

#!/usr/bin/env perl
use strict;
use warnings;
my $count = 0;
my $fg = "\x1b[38;5;";
my $bg = "\x1b[48;5;";
my $rs = "\x1b[0m";

sub swatch
{
    my $color  = shift;
    my $number = sprintf '%3d', $color;
    return "${bg}${color}m ${number} ${rs} ${fg}${color}m${number}${rs} ";
}

# display the colors
# first the system ones:
print "System colors:\n";
for my $color (0..15) {
    print swatch($color);
    print "\n" unless ++$count % 8;
}
print "\n";

# now the color cube
$count = 0;
print "Color cube, 6x6x6:\n";
for my $color (16..231) {
    print swatch($color);
    print "\n" unless ++$count %  6;
    print "\n" unless   $count % 36;
}

# now the grayscale ramp
$count = 0;
print "Grayscale ramp:\n";
for my $color (232..255) {
    print swatch($color);
    print "\n" unless ++$count % 12;
}