From: ahoward@... (ara howard)
Date: 2002-08-20T03:08:43+09:00
Subject: Re: How do I dup file descriptors in ruby?  (diverting STDERR)

i'm not sure why, but modifying the constants STDOUT and STDERR seems
to give the 'expected' behavior both with the calling process and
withing sub-processes (backquoted sub-shell expressions).  i tried all
manner of delegation, inheritance, extension - but the following is
simple and works like it reads :


===============================================================================
#!/usr/bin/env ruby


# save everything for restoration
IN  = STDIN.clone
ERR = STDERR.clone
OUT = STDOUT.clone

# the log file
$log = open 'logfile', 'w'

# redirect STDOUT to logfile
STDOUT.reopen $log
# merge STDERR and STDOUT
STDERR.reopen STDOUT

# output goes to logfile
`ls non_existent_file`

# output goes to logfile
$stderr.puts 'foo'

# output goes to logfile
$stdout.puts 'bar'

# output goes to logfile
puts 'end test 0'


# unmerge STDERR
STDERR.reopen ERR

# output goes to stderr
`ls non_existent_file`

# output goes to stderr 
$stderr.puts 'foo'

# STDOUT still points to logfile...
# output goes to logfile
$stdout.puts 'bar'

# output goes to logfile
puts 'end test 1'

===============================================================================

i am still very confused as to why asigning to $stdout is so much
different that modifying STDOUT - especially when concerning
sub-processes...

-ara