> > system("cat cab.??|tar vxz -C ${DESTDIR}");
>
> Here your "${DESTDIR}" is being interpolated to use perl's DESTDIR
variable instead of the shell's. Is this what you intended (is it even set,
are you running with strict and warnings?) Other than that it should be
working I believe. Are you getting an error result? You should check for
one by adding an 'or die ("Couldn't tar files: $!")' or some such to the
system call, or check the return value ($?).
.... yeh I know, I didnt want to write an ungly system call, this is what I
am really using.....
system("cat cab.??|tar vxz -C \$\{DESTDIR\}");
following up on ...> Remember your script runs in Perl not in the shell, you
run the perl interpreter in the shell, and I believe Perl uses whatever
shell is default on the system for how to run its "system" calls, aka most
likely /bin/sh (which could be pointed to tcsh, but may not)<...
I will probebly go with expanding a variable set with in my script. By the
way is there a way to find which shell is default, I am developing on
FreeBSD and sh is the default shell, but I will be runing these scripts as
root, and tcsh is the default root shell, this would be of segnificance.
>To maintain the shell's environment if this can't be handled in Perl, you
may be able to string commands together in one >command to system separated
by ;'s like on the command line, but this I am not sure about.
will look into that.
Thanx,
Mark
----- Original Message -----
From: <[EMAIL PROTECTED]>
To: "Mark Goland" <[EMAIL PROTECTED]>; "perl" <[EMAIL PROTECTED]>
Sent: Wednesday, January 15, 2003 2:04 PM
Subject: RE: waitpid
>
> ------------------------------------------------
> On Wed, 15 Jan 2003 12:55:39 -0500, Mark Goland <[EMAIL PROTECTED]>
wrote:
>
> > Hello Perl lovers,
> >
> > I am developing a script which runs in TCSH 6.x shell. I have two
questions
> >
>
> Remember your script runs in Perl not in the shell, you run the perl
interpreter in the shell, and I believe Perl uses whatever shell is default
on the system for how to run its "system" calls, aka most likely /bin/sh
(which could be pointed to tcsh, but may not).
>
> > 1. I need to be able to set an global enviernment variable. The shell
has a
> > build in command setenv which would enable me to do what I need. This is
> > what I try,
> >
> > system("setenv DESTDIR /mnt");
> >
>
> This is most likely succeeding (assuming the shell accepts it all) but I
would imagine the shell is started, the command is run, and the shell is
closed. So your subsequent call to the shell will be invoked in a new
instance of the environment, without what you set. But it appears there is
no reason to use this, at least not in this code segment, see below.
>
>
> > ...but this fails , by hand in works great. Source has the same problme.
Any
> > ideas ???
> >
> > 2. I need to run a few external commands sequantialy. Run one wait on
it to
> > compleate run the others.... a sample command would be
> >
> > system("cat cab.??|tar vxz -C ${DESTDIR}");
>
> Here your "${DESTDIR}" is being interpolated to use perl's DESTDIR
variable instead of the shell's. Is this what you intended (is it even set,
are you running with strict and warnings?) Other than that it should be
working I believe. Are you getting an error result? You should check for
one by adding an 'or die ("Couldn't tar files: $!")' or some such to the
system call, or check the return value ($?).
>
> >
> > In C I would usually fork and waitpid on child, I was wondering if
there is
> > a short trick to this in Perl. ( I know IPC::OpenX returns pid and I can
do
> > a waitpid on it ) .
> >
>
> How do you mean "short trick" ... it seems IPC::OpenX would be the short
trick, the normal way will work as you mentioned, to fork, and then waitpid
on that child, of course within that fork you are probably still looking at
doing a 'system'. 'system' just encapsulates the fork/waitpid process for
you, so you don't gain anything by first forking. To maintain the shell's
environment if this can't be handled in Perl, you may be able to string
commands together in one command to system separated by ;'s like on the
command line, but this I am not sure about.
>
> HTH a little, Good luck...
>
> http://danconia.org
>
> --
> To unsubscribe, e-mail: [EMAIL PROTECTED]
> For additional commands, e-mail: [EMAIL PROTECTED]
>
--
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
