use strict;
use warnings;
use Time::HiRes 'time';

my $doc = "'C-3PO' or 'See-Threepio' is a humanoid robot character from the [[Star Wars]] universe who appears in the original ''Star Wars'' films, the prequel trilogy and the sequel trilogy.\n";

$doc .= $doc for 1 .. 22;      ## expand string to 724 MB

print "length   : ", length($doc), "\n";  # 759169024

my $start = time;

# $doc =~ s/\[\[//g;           ##  8.626 secs.
# $doc =~ s/\]\]//g;
# $doc =~ s/\'//g;

# $doc =~ s/\[//g;             ## 10.493 secs.
# $doc =~ s/\]//g;
# $doc =~ s/\'//g;

# $doc =~ s/\[+//g;            ##  7.050 secs.
# $doc =~ s/\]+//g;
# $doc =~ s/\'+//g;

# $doc =~ s/(?:\[|\]|\')//g;   ## 19.559 secs.
# $doc =~ s/(?:\[|\]|\')+//g;  ## 56.150 secs.  <- did not expect this

# $doc =~ s/[\[\]\']//g;       ##  9.072 secs.
# $doc =~ s/[\[\]\']+//g;      ##  6.915 secs.

  $doc =~ tr/[]'//d;           ##  1.908 secs.

printf "duration : %7.03f secs.\n", time - $start;

print  "length   : ", length($doc), "\n";  # 708837376