Re: [Boston.pm] script works ok on command line, hangs when run from shell script

Do you have to use csh, or are you just restricted from using bash?  For instance, could you use perl instead of csh?

So, replace this script (not sure the name, so I'll just paste it here):

#!/bin/csh

tool -options -nobuffer | filter.pl


With this (warning - untested and may include typos):

#!/opt/perl_5.8.8/bin/perl
use warnings;
use strict;
# turn off stdout buffering... hopefully.
$|=1;

open (my $fd, "tool -options -nobuffer|") || die "ERMAHGERD!\n";

while(my $line = <$fd>) {
  if($line=~s///) {
          if($line=~s///){
          }
  }

  print $line;
}
close $fd;

Also, if the lines are really long, you might want to change $/.  For instance, if your regex lines are s/;/\n/g, maybe you should do $/=";".  Considering you seem to care about output buffering, this will probably help.

Duane

> On Apr 29, 2017, at 9:09 PM, Greg London <[email protected]> wrote:
> 
> So, this is a work thing, and work is kinda weird about what you can
> and cannot use.  We have to use csh. We are also using clearcase,
> with a gui from the 1980's. I have worked on military classified
> projects, and my current company is the strictest place I've ever
> worked at. And we do consumer parts.
> 
> Anyway, I talked with someone who is like quasi IT for our group
> He couldnt figure it out. So he filed a ticket, and it has gone to
> our actual IT group, which is all based in europe. Apparently
> having IT people in the same building you work in is 'inefficient'
> 
> I am doing a workaround for now.
> If I ever find out what the issue is, I'll let folks know.
> 
> I will say that I didnt know anything about cshell scriots
> until now, and boy I wish I hadnt.  I would have madd the whold
> scrit perl, but I am trying to boot something onto an existing
> project.
> 
> Greg
> 
> 
> On Thu, April 27, 2017 1:02 pm, Andrew Feren wrote:
>> I'd definitely start by not using csh. It has a pile of problems as a
>> scripting language. Especially related to pipes and file descriptors.
>> 
>> http://www.faqs.org/faqs/unix-faq/shell/csh-whynot/
>> 
>> 
>> -Andrew
>> 
>> 
>>> On Apr 27, 2017, at 11:18, Bill Ricker <[email protected]> wrote:
>>> 
>>> 
>>> Apparently i replied off-list.  Here's my reply for those following
>>> along at home.
>>> 
>>> // Bill
>>> 
>>> 
>>> ---------- Forwarded message ----------
>>> 
>>> 
>>> 
>>> Is your interactive commandline provided by (ba)sh or [tcz]sh ?
>>> I see your script is Csh.
>>> That's one possible difference since that's where the pipe is actually
>>> created and sub-process spawned.
>>> 
>>> $| won't
>>> ​do what you want.
>>> 
>>> 
>>> perldoc -v '$|'
>>> 
>>> HANDLE->autoflush( EXPR )
>>> $OUTPUT_AUTOFLUSH
>>> $|
>>> 
>>> 
>>> If set to nonzero, forces a flush right away and after every write or
>>> print on the currently selected output channel. Default is 0 (regardless
>>> of whether the channel is really buffered by the system or not; $| tells
>>> you only whether you've asked Perl explicitly to flush after each
>>> write). STDOUT will typically be line buffered if output is to the
>>> terminal and block buffered otherwise. Setting this variable is useful
>>> primarily when you are outputting to a pipe or socket, such as when you
>>> are running a Perl program under rsh and want to see the output as it's
>>> happening. This has no effect on input buffering. See getc for that. See
>>> select on how to select the output channel. See also IO::Handle.
>>> 
>>> Mnemonic: when you want your pipes to be piping hot.
>>> 
>>> 
>>> ​ If you want actual non-blocking output in an output pipe or to a
>>> file, I _think_ you'll need
>>> ​
>>> perldoc IO::Handle
>>> 
>>> ​*$io->blocking ( [ BOOL ] )*
>>> 
>>> 
>>> If called with an argument blocking will turn on non-blocking IO if
>>> BOOL is
>>> false, and turn it off if BOOL is true.
>>> 
>>> blocking will return the value of the previous setting, or the current
>>> setting if BOOL is not given.
>>> 
>>> If an error occurs blocking will return undef and $! will be set.
>>> ​as in
>>> $io->blocking( 0 ) or croak "$!: io->blocking ( 0 )";
>>> 
>>> 
>>> ​the "sub init" for SSL-capable netcat script "scnc" does :
>>> 
>>> 
>>> $SIG{INT}  = sub { $self->exit };
>>> $SIG{CHLD} = 'IGNORE';
>>> 
>>> 
>>> STDOUT->blocking(0);
>>> STDOUT->autoflush(1);
>>> STDIN->blocking(0);
>>> STDIN->autoflush(1);
>>> ​
>>> 
>>> 
>>> _______________________________________________
>>> Boston-pm mailing list
>>> [email protected]
>>> http://mail.pm.org/mailman/listinfo/boston-pm
>>> 
>> 
>> _______________________________________________
>> Boston-pm mailing list
>> [email protected]
>> http://mail.pm.org/mailman/listinfo/boston-pm
> 
> 
> -- 
> 
> _______________________________________________
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Duane Bronson
[email protected] <mailto:[email protected]>
http://www.nerdlogic.com/ <http://www.nerdlogic.com/>
5 Goden St.
Belmont, MA 02478
617.515.2909





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