Switching between output to file and STDOUT

loris has asked for the wisdom of the Perl Monks concerning the following question:

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Re: Swiching between output to file and STDOUT by davorg (Chancellor) on Nov 09, 2004 at 13:58 UTC
`if (defined $outfile) { open OUTPUT, '>', $outfile; select OUTPUT; } # then just use "print"` [download] Update: Fletch is right. I've removed the misleading reference to STDOUT. -- <http://www.dave.org.uk> "The first rule of Perl club is you do not talk about Perl club." -- Chip Salzenberg	[reply] [d/l]
Re^2: Swiching between output to file and STDOUT by Fletch (Bishop) on Nov 09, 2004 at 14:16 UTC
And by "then just print to STDOUT" he means "just print without specifying a filehandle" (e.g. `print "foo\n"`). Even if you change the default output handle with `select OUTPUT` the statement `print STDOUT "foo"` will still print to stdout.	[reply] [d/l] [select]
Re: Swiching between output to file and STDOUT by borisz (Canon) on Nov 09, 2004 at 14:00 UTC
`$out = STDOUT{IO};` [download] or `$out = \STDOUT;` [download] Boris	[reply] [d/l] [select]
Re: Swiching between output to file and STDOUT by thor (Priest) on Nov 09, 2004 at 20:43 UTC
I was going to reply with the special file "-" (as documented in perlopentut), but I found an inconsistency between 2-arg and 3-arg open. If I do this `open(OUTPUT, '>-') or die; print OUTPUT "foo\n";` [download] I get "foo\n" on standard out. However, if I use 3-arg open like so: `open(OUTPUT, ">", '-') print "foo\n";` [download] I get the output directed to a file called '-'. This seems like it might be a bug...can anyone point me to somewhere in the docs where this is documented behavior? thor `Feel the white light, the light within Be your own disciple, fan the sparks of will For all of us waiting, your kingdom will come`	[reply] [d/l] [select]
Re^2: Swiching between output to file and STDOUT by edan (Curate) on Nov 11, 2004 at 10:31 UTC
This seems like it might be a bug...can anyone point me to somewhere in the docs where this is documented behavior? Certainly. `perldoc open` (at least, my local pod) states: `In the 2-arguments (and 1-argument) form opening '-' opens STDIN and opening '>-' opens STDOUT.` [download] It specifically declines to mention 3-arg `open`. -- edan	[reply] [d/l]
Re^2: Swiching between output to file and STDOUT by gaal (Parson) on Nov 11, 2004 at 10:46 UTC
It isn't a bug. 3-arg `open` is the magicless form of the call, and is exactly what you should use when you do want to open a file named "-". It's a bit safer in other places too, because it doesn't make pipes of '\|' characters. "../" still goes up a dir, though.	[reply] [d/l]
Re: Swiching between output to file and STDOUT by saintmike (Vicar) on Nov 09, 2004 at 21:10 UTC
Since what you're doing looks like logging, why not go full throttle and use Log::Log4perl: `my $outfile; use Log::Log4perl qw(:easy); Log::Log4perl->easy_init( {level => $DEBUG, file => (defined $outfile ? $outfile : "STDOUT")}); DEBUG "hey!";` [download]	[reply] [d/l]