je

#!/usr/bin/env ruby
# Help
def usage
  puts <<END
  Usage: je [ARGS]...
  
  Options:
    -v        verbose mode
    --version show version
END
  exit
end

# Option parsing
$verbose = false
$sys_jemalloc = '/usr/lib/x86_64-linux-gnu/libjemalloc.so.2'
argv = ARGV
usage() if argv.length == 0
if argv[0] == '-v'
  $verbose = true
  argv = argv[1..-1]
elsif argv[0] == '--version'
  require 'jemalloc/version'
  puts "jemalloc version #{JEMalloc::VERSION}"
  exit
end
usage() if argv.length == 0

# Set ENV for preloading jemalloc
lib_dir = File.expand_path('../lib/', File.dirname(__FILE__))
if File.exist? (lib_dir + "/jemalloc.so")
  puts "=> Injecting jemalloc..." if $verbose
  ENV.store("LD_PRELOAD", lib_dir + "/jemalloc.so")
elsif File.exist? (lib_dir + "/jemalloc.bundle")
  puts "=> Injecting jemalloc..." if $verbose
  ENV.store("DYLD_INSERT_LIBRARIES", lib_dir + "/jemalloc.bundle")
elsif File.exist? ($sys_jemalloc)
  puts "=> Injecting jemalloc..." if $verbose
  ENV.store("LD_PRELOAD", $sys_jemalloc)
else
  puts "=> Can't inject, jemalloc not found"
end

Kernel.exec *argv