Re: how to set environmental vars

So, How do I source a env csh file and make sure.

Consider the following:

#!/usr/bin/perl -w
 
 
source_it() unless $ENV{foo};
 
printf "%s = %s\n",$_,$ENV{$_} foreach keys %ENV;
 
exit(0);
 
 
sub source_it{
    exec "echo 'source env.csh ; perl $0' | csh -s";
}
[download]

I tested it, it works.

What I'm doing here is looking for a variable that I know should have been set by the sourced in file and if it isn't set I call the sub that execs off a "one-liner" to invoke csh, source in the environment and then re-execute the script. Once that happens the variable I'm looking for is set and I just continue to execute the script as planned. This will work with ksh, bash, sh, with differing command line switches.

This has the additional advantage is that in the event one or more of the values is the result of a scriplet or function buried in the sourced in file it still works. Just parsing the setenv lines won't make that happen.

Peter L. Berghold -- Unix Professional
Peter -at- Berghold -dot- Net; AOL IM redcowdawg Yahoo IM: blue_cowdawg

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Re^2: how to set environmental vars by ikegami (Patriarch) on Nov 10, 2005 at 23:59 UTC
In your solution: There's a potential for an infinite loop. You're running one shell and one shell command more than you need. You're vulnerable to two injection attacks. (Only one fixed) You're not passing parent Perl's arguments to the child Perl. (Not fixed) You're not passing parent Perl's switches to the child Perl. (Not fixed) Fix: `#!/usr/bin/perl -w if (!defined($ENV{foo})) { if (@ARGV > 0 && $ARGV[0] eq 'nested') { die("Unable to find value for env var FOO\n"); } exec 'csh', '-c', "source env.csh ; perl $0 nested"; die("Unable to execute csh: $!\n"); } printf "%s = %s\n",$_,$ENV{$_} foreach keys %ENV;` [download]	[reply] [d/l]
Re^3: how to set environmental vars by blue_cowdawg (Monsignor) on Nov 11, 2005 at 03:33 UTC
While we're at fixing each other's code: `\| \| exec '/bin/csh', '-c', "source env.csh ; perl $0 nested"; \| \|` [download] You forgot about the issue of an executable being in `$PATH` and being executed instead of the shell we are after. As far as an infinite loop is concerned I did state that I am testing for a variable that I know exists and is set in the `env.csh` file. Fixing the last two bullet items you are referring to is not covered in fix either AFAICT. Any arguments being passed to the script are going to be lost. To fix that I'd add `exec '/bin/csh', '-c', sprintf("source env.csh ; perl $0 nested %s" +,join(" ",@ARGV));` [download] And believe it or not there are still some ways to break this...	[reply] [d/l] [select]
Re^4: how to set environmental vars by ikegami (Patriarch) on Nov 11, 2005 at 03:41 UTC
ack! `join(" ", @ARGV)`???? What if there are spaces or special characters? You've just added another bug and another injection attack. This is getting very complicated. And this my point. Compare this to the simple solution I posted, which has none of these problems.	[reply] [d/l]
Re^4: how to set environmental vars by rsennat (Beadle) on Nov 11, 2005 at 09:54 UTC
I get an error with the code, sorry if I miss anything silly. `#!/usr/bin/perl -w if (!defined($ENV{foo})) { if (@ARGV > 0 && $ARGV[0] eq 'nested') { die("Unable to find value for env var FOO\n"); } exec '/bin/csh', '-c', sprintf("source script1.csh ; perl $0 nested %s +",join(" ",@ARGV)); die("Unable to execute csh: $!\n"); } printf "%s = %s\n",$_,$ENV{$_} foreach keys %ENV;` [download] The script1.csh `setenv PATH_ORIG "${PATH}" setenv MANPATH_ORIG "${MANPATH}" setenv LD_LIBRARY_PATH_ORIG "${LD_LIBRARY_PATH}"` [download] And the Error I get is Missing $ on loop variable at tmp.pl line 13. Please help me out... Thanks	[reply] [d/l] [select]