sub maxprefix {
  my $p = quotemeta shift;
  for (@_) { chop $p until /^$p/ }
  return $p;
}

[download]

This will still often fail on metacharacters because you'll get a "trailing \ in regexp" error. 

sub maxprefix {
    my $p = shift(@_);
    for(@_) { chop $p  until /^\Q$p/ }
    return $p;
}

[download]

Update: The one you added has problems as well: 

sub maxprefix {
  my $s = reverse shift;
  my $p = '';
  for (@_) { $p .= quotemeta chop $s while /^$p/ }
  chop $p;
  return $p;
}

[download]

It will find the maximum prefix between the first string and the string of the others that has the longest common prefix with the first string: 

print maxprefix("testing","terse","tester","time"),$/;

[download]
prints test not t.

                - tye

In reply to Re^3: Find common prefix from a list of strings (trailing \) by tye
in thread Find common prefix from a list of strings by Albannach

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