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Home: Perl Programming Help: Advanced: Problem with Perl 'system' comand

barryk New User May 26, 2010, 7:41 AM Post #1 of 6 (6082 views) Problem with Perl 'system' comand Can't Post At the office we run an AIX ver 5 rel 3 system. We have a Perl script that given its parameters makes a decision on how to call several other programs. One of the programs that it calls is a compiled C program. I was having problems so I investigated and found that an environment variable that is known to the Perl script is not received by the compiled C program. The Perl script uses the Perl 'system' function to run the compiled C program. According to the information I found for AIX the limit of parameters and environment variables is very large for our system, so that is not the problem. Any ideas as to why an environment variable gets lost when the C program is called ?

shawnhcorey Enthusiast May 26, 2010, 9:33 AM Post #2 of 6 (6078 views) Re: [barryk] Problem with Perl 'system' comand [In reply to] Can't Post Does the system command call it as a string or a list. As a string, it starts a shell, which may change the environment depending on the user. Normally, it uses the POSIX shell, sh(1). __END__ I love Perl; it's the only language where you can bless your thingy. Perl documentation is available at perldoc.perl.org. The list of standard modules and pragmatics is available in perlmodlib. Get Markup Help. Please note the markup tag of "code".

rovf Veteran May 27, 2010, 8:31 AM Post #3 of 6 (6068 views) Re: [barryk] Problem with Perl 'system' comand [In reply to] Can't Post This can't be. The enivironment is passed to the subprocesses. Did you print $ENV{YOURVARIABLE} *right* before invoking system(), and also print getenv("YOURVARIABLE") just in the beginning of your main() function in the C program? I bet they don't disappear inbetween.

barryk New User May 27, 2010, 11:41 AM Post #4 of 6 (6055 views) Re: [barryk] Problem with Perl 'system' comand [In reply to] Can't Post Thanks to all who replied to my posting. I have finally solved the problem. The problem was that I set the value of the environment variable from the command line, next I ran the Perl script which ran the compiled C program by passing a single string to system(). When system() fork'ed a shell to run the specified C program it read my $HOME/.kshrc file which contained another definition of the environment variable which ended up overwriting the value I had entered manually from the command line.

rovf Veteran May 28, 2010, 8:19 AM Post #5 of 6 (6027 views) Re: [barryk] Problem with Perl 'system' comand [In reply to] Can't Post You should always unset $ENV{ENV} before shelling out to ksh...

rovf Veteran Jun 28, 2010, 2:51 AM Post #6 of 6 (5414 views) Re: [barryk] Problem with Perl 'system' comand [In reply to] Can't Post I wonder why system() was calling ksh in your case. It is supposed to use Bourne Shell....

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