NAME systemu SYNOPSIS univeral capture of stdout and stderr and handling of child process pid for windows, *nix, etc. URIS http://github.com/ahoward/systemu http://rubyforge.org/projects/codeforpeople/ INSTALL gem install systemu HISTORY 2.0.0 - versioning issue. new gem release. 1.3.1 - updates for ruby 1.9.1 1.3.0 - move to github 1.2.0 - fixed handling of background thread management - needed Thread.current.abort_on_exception = true - fixed reporting of child pid, it was reported as the parent's pid before SAMPLES <========< samples/a.rb >========> ~ > cat samples/a.rb # # systemu can be used on any platform to return status, stdout, and stderr of # any command. unlike other methods like open3/popen4 there is zero danger of # full pipes or threading issues hanging your process or subprocess. # require 'systemu' date = %q( ruby -e" t = Time.now; STDOUT.puts t; STDERR.puts t " ) status, stdout, stderr = systemu date p [ status, stdout, stderr ] ~ > ruby samples/a.rb [#, "2011-09-13 20:50:37 -0600\n", "2011-09-13 20:50:37 -0600\n"] <========< samples/b.rb >========> ~ > cat samples/b.rb # # quite a few keys can be passed to the command to alter it's behaviour. if # either stdout or stderr is supplied those objects should respond_to? '<<' # and only status will be returned # require 'systemu' date = %q( ruby -e" t = Time.now; STDOUT.puts t; STDERR.puts t " ) stdout, stderr = '', '' status = systemu date, 'stdout' => stdout, 'stderr' => stderr p [ status, stdout, stderr ] ~ > ruby samples/b.rb [#, "2011-09-13 20:50:37 -0600\n", "2011-09-13 20:50:37 -0600\n"] <========< samples/c.rb >========> ~ > cat samples/c.rb # # of course stdin can be supplied too. synonyms for 'stdin' include '0' and # 0. the other stdio streams have similar shortcuts # require 'systemu' cat = %q( ruby -e" ARGF.each{|line| puts line} " ) status = systemu cat, 0=>'the stdin for cat', 1=>stdout='' puts stdout ~ > ruby samples/c.rb the stdin for cat <========< samples/d.rb >========> ~ > cat samples/d.rb # # the cwd can be supplied # require 'systemu' require 'tmpdir' pwd = %q( ruby -e" STDERR.puts Dir.pwd " ) status = systemu pwd, 2=>(stderr=''), :cwd=>Dir.tmpdir puts stderr ~ > ruby samples/d.rb /private/var/folders/nO/nOjBCb30ELegrm98Bhyvbk+++TM/-Tmp- <========< samples/e.rb >========> ~ > cat samples/e.rb # # any environment vars specified are merged into the child's environment # require 'systemu' env = %q( ruby -r yaml -e" puts ENV[ 'answer' ] " ) status = systemu env, 1=>stdout='', 'env'=>{ 'answer' => 0b101010 } puts stdout ~ > ruby samples/e.rb 42 <========< samples/f.rb >========> ~ > cat samples/f.rb # # if a block is specified then it is passed the child pid and run in a # background thread. note that this thread will __not__ be blocked during the # execution of the command so it may do useful work such as killing the child # if execution time passes a certain threshold # require 'systemu' looper = %q( ruby -e" loop{ STDERR.puts Time.now.to_i; sleep 1 } " ) status, stdout, stderr = systemu looper do |cid| sleep 3 Process.kill 9, cid end p status p stderr ~ > ruby samples/f.rb # "1315968638\n1315968639\n1315968640\n"