Temporary disable $stdout

gistfile1.rb

/* Temporary disable $stdout
============================

This method works for Ruby and new sub-processes.

I have seen other techniques on the net which re-assign $stdout with another IO,
but then the sub-processes will still use the old stdout.

*/

def dev_null(&block)
  begin
    orig_stdout = $stdout.dup # does a dup2() internally
    $stdout.reopen('/dev/null', 'w')
    yield
  ensure
    $stdout.reopen(orig_stdout)
  end
end

gistfile2.sh

#
# And now, the same for POSIX shells. Got help from http://tldp.org/LDP/abs/html/io-redirection.html
#

dev_null () {
  # FIXME: how do we know if 3 is taken ?
  exec 3>&1
  exec 1>/dev/null
  $@
  exec 1>&3
  exec 3>&- # closes fd3, which is done by GC in ruby
}

# Forget this, in bash you can just redirect the output on the command :

dev_null () {
  $@ >/dev/null
}

Shortened.

  def dev_null
    orig_stdout = $stdout.dup # does a dup2() internally
    $stdout.reopen('/dev/null', 'w')
    yield
  ensure
    $stdout.reopen(orig_stdout)
  end