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

my $textlength=3;
my $numlength=1;  # on purpose too narrow

my $fmt = "%-$textlength".'s '."%$numlength"."d\n";
print "format is:$fmt";
printf $fmt, "a",1;
printf $fmt, "abc",123;
printf $fmt, "abcdef",12345;

__END__
prints:
format is:%-3s %1d
a   1
abc 123
abcdef 12345