with-memory-limit utility program

with-memory-limit

!/usr/bin/perl

use BSD::Resource qw(setrlimit RLIMIT_VMEM RLIM_INFINITY);
my ($mem) = shift // usage();
@ARGV or usage();
my ($n, $s) = $mem =~ /\A (\d+) ([kmgKMG]?) \z/x or usage();
my $suf = { k => 1024,
            m => 1024 * 1024,
            g => 1024 * 1024 * 1024,
          };

if ($s) {
  if (exists $suf->{lc $s}) {
    $n *= $suf->{lc $s};
  } else {
    usage();
  }
}

setrlimit(RLIMIT_VMEM,  $n , RLIM_INFINITY) or die "setrlimit: $!";
exec @ARGV;
die "$ARGV[0]: $!\n";

sub usage {
  die "usage: with-memory-limit AMOUNT command args...
  AMOUNT is a number with an optional suffix of k, m, or g.\n";
}