Empirically, Perl's glob does not call the system glob. On my Linux system Perl (5.18.2) is slow but the system glob is fast. Create a file named /tmp/glob/$(pe

Empirically, Perl's glob does not call the system glob. On my Linux system Perl (5.18.2) is slow but the system glob is fast. Create a file named /tmp/glob/$(perl -e 'print "a"x100') in an otherwise empty /tmp/glob and then try: $ cat tglob.pl #!/usr/bin/perl use Time::HiRes qw(clock_gettime); $| = 1; chdir "/tmp/glob" || die "$!"; for($i=0; $i<9; $i++) { $pattern = ("a*"x$i) . "b"; $t = clock_gettime(CLOCK_REALTIME); $mul = 10; if($i >= 5){ $mul = 1; } for($j=0; $j<$mul; $j++) { glob $pattern; } $t1 = clock_gettime(CLOCK_REALTIME); printf("%d %.9f\n", $i, ($t1-$t)/$mul); } $ perl -v This is perl 5, version 18, subversion 2 (v5.18.2) built for x86_64-linux-gnu-thread-multi ... $ perl tglob.pl 0 0.000004911 1 0.000016212 2 0.000088072 3 0.002416682 4 0.030226517 5 0.452545881 6 6.872966528 ^C You're the second person to claim that Perl calls the system glob though (someone in my blog comments did too). Maybe different versions of Perl do different things? This is Ubuntu 14.04 if that matters.