#!/usr/bin/perl
use strict;
use warnings;

my $max_len = 6;
for my $i (
	"  ab ", 
	"  ab   ", 
	"  abc   ", 
	"  abcd   ", 
	"  abcde   ", 
	"  abcdef   ", 
	"  abcdefg   "
) {
    my $o = $i;
    while (length $o > $max_len and $o =~ s/\s$//){}
    while (length $o > $max_len and $o =~ s/^\s//){}
    while (length $o > $max_len and $o =~ s/.$//){}
    printf "%-15s%s", qq("$i"), qq( => "$o"\n);
}