chrise@hpnmdla.HP.COM (Chris Eich) (06/15/90)
Two questions about `` (backticks):
1. Is there an easier way than:
@array = split(/\n/, `command`);
to fill an array with each line of `command`? (I'm not complaining,
as this is pretty easy; just curious.)
2. How can I catch the stderr of `command`? In the shell, I can do:
result=`command 2>&1`
I can't see how to do it in perl.
Chrischrise@hpnmdla.HP.COM (Chris Eich) (06/15/90)
Let me amend my two questions:
1. Is there an easier way than:
@array = split(/\n/, `command`);
to fill an array with each line of `command`? (I'm not complaining,
as this is pretty easy; just curious.)
I guess I'd like `command` to return an array of lines when in an array
context, just as <FILE> does.
2. How can I catch the stderr of `command`? In the shell, I can do:
result=`command 2>&1`
I can't see how to do it in perl.
Never mind!!! I left a newline on a variable I put at the end of
"command", causing the redirection to be lost.
Christneff@bfmny0.BFM.COM (Tom Neff) (06/15/90)
>| 2. How can I catch the stderr of `command`? In the shell, I can do: >| result=`command 2>&1` >You just did it! > >You just can't get both stdout and stderr in *separate* places, unless >you muss with fork() and pipe() yourself. Wellllll... tmpf = "/tmp/xx.$$"; result = `command 2>$tmpf`; reserr = `cat $tmpf; rm -f $tmpf`; -- Annex Canada now! We need the room, \) Tom Neff and who's going to stop us. (\ tneff@bfmny0.BFM.COM
merlyn@iwarp.intel.com (Randal Schwartz) (06/15/90)
In article <8310004@hpnmdla.HP.COM>, chrise@hpnmdla (Chris Eich) writes: | 1. Is there an easier way than: | | @array = split(/\n/, `command`); | | to fill an array with each line of `command`? (I'm not complaining, | as this is pretty easy; just curious.) That's what I've been using. With my luck, Larry will probably post something that does it in half-a-character, or something. :-) | 2. How can I catch the stderr of `command`? In the shell, I can do: | | result=`command 2>&1` | | I can't see how to do it in perl. You just did it! $result = `perl -e 'print STDERR "hello world\n"' 2>&1`; print "<$result>"; You just can't get both stdout and stderr in *separate* places, unless you muss with fork() and pipe() yourself. print `perl -e 'print STDERR "Just another Perl hacker,"' 2>&1` -- /=Randal L. Schwartz, Stonehenge Consulting Services (503)777-0095 ==========\ | on contract to Intel's iWarp project, Beaverton, Oregon, USA, Sol III | | merlyn@iwarp.intel.com ...!any-MX-mailer-like-uunet!iwarp.intel.com!merlyn | \=Cute Quote: "Welcome to Portland, Oregon, home of the California Raisins!"=/
merlyn@iwarp.intel.com (Randal Schwartz) (06/15/90)
In article <15592@bfmny0.BFM.COM>, tneff@bfmny0 (Tom Neff) writes: | >You just can't get both stdout and stderr in *separate* places, unless | >you muss with fork() and pipe() yourself. | | Wellllll... | | tmpf = "/tmp/xx.$$"; | result = `command 2>$tmpf`; | reserr = `cat $tmpf; rm -f $tmpf`; Hey, a tempfile is just a pipe with an attitude and a strong will to live... :-) -- /=Randal L. Schwartz, Stonehenge Consulting Services (503)777-0095 ==========\ | on contract to Intel's iWarp project, Beaverton, Oregon, USA, Sol III | | merlyn@iwarp.intel.com ...!any-MX-mailer-like-uunet!iwarp.intel.com!merlyn | \=Cute Quote: "Welcome to Portland, Oregon, home of the California Raisins!"=/
dglo@ADS.COM (Dave Glowacki) (06/16/90)
In article <1990Jun15.013714.24031@iwarp.intel.com> merlyn@iwarp.intel.com (Randal Schwartz) writes: >In article <8310004@hpnmdla.HP.COM>, chrise@hpnmdla (Chris Eich) writes: >| 2. How can I catch the stderr of `command`? In the shell, I can do: >| >| result=`command 2>&1` >| >| I can't see how to do it in perl. > >You just did it! > > $result = `perl -e 'print STDERR "hello world\n"' 2>&1`; > print "<$result>"; Is this guaranteed, even if the user's shell (or SHELL environment variable) is set to /bin/csh? If so, is this also true for pipes-as-filehandles (as in: open(SOMETHING, "|program >logfile 2>&1"); or something like that? -- Dave Glowacki dglo@ads.com Advanced Decision Systems
lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall) (06/17/90)
In article <72A$+6+@ads.com> dglo@ADS.COM (Dave Glowacki) writes:
[old stuff deleted]
: > $result = `perl -e 'print STDERR "hello world\n"' 2>&1`;
: > print "<$result>";
:
: Is this guaranteed, even if the user's shell (or SHELL environment variable)
: is set to /bin/csh?
:
: If so, is this also true for pipes-as-filehandles (as in:
: open(SOMETHING, "|program >logfile 2>&1");
: or something like that?
Yes and yes. The internal routine do_exec() explicity calls /bin/sh.
This is how most popen()s and system()s work. The SHELL environment variable
should mostly be reserved for specifying the desired *interactive* shell,
in my opinion. Otherwise it only obfuscates portability.
If you want to execute a command using /bin/csh, invoke /bin/csh directly.
Larry