URIS
http://rubyforge.org/frs/?group_id=1024
http://www.codeforpeople.com/lib/ruby/
SYNOPSIS
open child process with handles on pid, stdin, stdout, and stderr
HISTORY
0.3.0 :
- bug fix from jordan breeding. general clean up. added spawn method.
0.2.0 :
- added exception marshaled from child -> parent when exec fails. thanks
to jordan breeding for a patch (yay!) and paul brannan for this most
excellent idea.
0.1.0 :
- fixed docs to correctly show return value of popen4 (pid first not last).
thanks Stefanie Tellex <stefie10@alum.mit.edu> for catching this.
0.0.0 :
- initial version
INSTALL
~> gem install open4
SAMPLES
···
----------------------------------------------------------------------------
simple usage
----------------------------------------------------------------------------
harp: > cat sample/simple.rb
require "open4"
pid, stdin, stdout, stderr = Open4::popen4 "sh"
stdin.puts "echo 42.out"
stdin.puts "echo 42.err 1>&2"
stdin.close
ignored, status = Process::waitpid2 pid
puts "pid : #{ pid }"
puts "stdout : #{ stdout.read.strip }"
puts "stderr : #{ stderr.read.strip }"
puts "status : #{ status.inspect }"
puts "exitstatus : #{ status.exitstatus }"
harp: > ruby sample/simple.rb
pid : 17273
stdout : 42.out
stderr : 42.err
status : #<Process::Status: pid=17273,exited(0)>
exitstatus : 0
----------------------------------------------------------------------------
in block form - the child process is automatically waited for
----------------------------------------------------------------------------
harp: > cat sample/block.rb
require 'open4'
status =
Open4::popen4("sh") do |pid, stdin, stdout, stderr|
stdin.puts "echo 42.out"
stdin.puts "echo 42.err 1>&2"
stdin.close
puts "pid : #{ pid }"
puts "stdout : #{ stdout.read.strip }"
puts "stderr : #{ stderr.read.strip }"
end
puts "status : #{ status.inspect }"
puts "exitstatus : #{ status.exitstatus }"
harp: > ruby sample/block.rb
pid : 17295
stdout : 42.out
stderr : 42.err
status : #<Process::Status: pid=17295,exited(0)>
exitstatus : 0
----------------------------------------------------------------------------
exceptions are marshaled from child to parent if fork/exec fails
----------------------------------------------------------------------------
harp: > cat sample/exception.rb
require "open4"
Open4::popen4 "noexist"
harp: > ruby sample/exception.rb
/dmsp/reference/ruby-1.8.1//lib/ruby/site_ruby/open4.rb:100:in `popen4': No such file or directory - noexist (Errno::ENOENT)
from sample/exception.rb:3
----------------------------------------------------------------------------
the spawn method provides and even more convenient method of running a
process, allowing any object that supports 'each', 'read', or 'to_s' to be
given as stdin and any objects that support '<<' to be given as
stdout/stderr. an exception is thrown if the exec'd cmd fails (nonzero
exitstatus) unless the option 'raise'=>false is given
----------------------------------------------------------------------------
harp: > cat sample/spawn.rb
require 'open4'
include Open4
cat = ' ruby -e" ARGF.each{|line| STDOUT << line} " '
stdout, stderr = '', ''
status = spawn cat, 'stdin' => '42', 'stdout' => stdout, 'stderr' => stderr
p status
p stdout
p stderr
stdout, stderr = '', ''
status = spawn cat, 0=>'42', 1=>stdout, 2=>stderr
p status
p stdout
p stderr
harp: > RUBYLIB=lib ruby sample/spawn.rb
0
"42"
""
0
"42"
""
AUTHOR
LICENSE
ruby's
enjoy.
-a
--
be kind whenever possible... it is always possible.
- h.h. the 14th dali lama