Open3 grants you access to stdin, stdout, and stderr when running another program. Example:
require "open3" include Open3 stdin, stdout, stderr = popen3('nroff -man')
::popen3 can also take a block which will receive stdin, stdout and stderr as parameters. This ensures stdin, stdout and stderr are closed once the block exits. Example:
require "open3" Open3.popen3('nroff -man') { |stdin, stdout, stderr| ... }
Open stdin, stdout, and stderr streams and start external executable. Non-block form:
require 'open3' [stdin, stdout, stderr] = Open3.popen3(cmd)
Block form:
require 'open3' Open3.popen3(cmd) { |stdin, stdout, stderr| ... }
The parameter cmd
is passed directly to Kernel#exec.
# File open3.rb, line 46 def popen3(*cmd) pw = IO::pipe # pipe[0] for read, pipe[1] for write pr = IO::pipe pe = IO::pipe pid = fork{ # child fork{ # grandchild pw[1].close STDIN.reopen(pw[0]) pw[0].close pr[0].close STDOUT.reopen(pr[1]) pr[1].close pe[0].close STDERR.reopen(pe[1]) pe[1].close exec(*cmd) } exit!(0) } pw[0].close pr[1].close pe[1].close Process.waitpid(pid) pi = [pw[1], pr[0], pe[0]] pw[1].sync = true if defined? yield begin return yield(*pi) ensure pi.each{|p| p.close unless p.closed?} end end pi end