[ANN] systemu-1.2.0

[ara.t.howard]

NAME

systemu

SYNOPSIS

univeral capture of stdout and stderr and handling of child
process pid for windows, *nix, etc.

URIS

http://rubyforge.org/projects/codeforpeople/
http://codeforpeople.com/lib/ruby/
http://codeforpeople.rubyforge.org/svn/

INSTALL

gem install systemu

HISTORY

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

[#<Process::Status: pid=987,exited(0)>, "Thu Dec 06 16:01:59
-0700 2007\n", "Thu Dec 06 16:01:59 -0700 2007\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

[#<Process::Status: pid=992,exited(0)>, "Thu Dec 06 16:01:59
-0700 2007\n", "Thu Dec 06 16:01:59 -0700 2007\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/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

#<Process::Status: pid=1012,signaled(SIGKILL=9)>
"1196982119\n1196982120\n1196982121\n"


enjoy.


a @ http://codeforpeople.com/