You can save a couple of steps: 

my @strings = qw(
  /home/usernames/doejohnwilson
  x/home/usernames/doejanemary
);
my $common_length = ( $strings[0] ^ $strings[1] ) =~ /^\0*/ && $+[0];

print substr $strings[0], 0, $common_length;

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In reply to Re^2: Print left-anchored similarities between two strings by Anonymous Monk
in thread Print left-anchored similarities between two strings by miketosh

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