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Re: confused path

by choroba (Bishop)
on Oct 09, 2012 at 08:32 UTC ( #997953=note: print w/replies, xml ) Need Help??

in reply to confused path

Can you show some code that demonstrates the issue?
FindBin is not related to where system searches for executable files.
Does system $prog1; run the same programme as exec $prog1;?
لսႽ ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ

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Re^2: confused path
by skyworld_chen (Acolyte) on Oct 10, 2012 at 06:39 UTC

    thanks for reply. Let me explain what happened in detail: I need to transfer a simulation package from one internal network to another internal network in company. Though both networks use linux, there are some differences between them, such as tools setting etc.

    here is a piece of code from one script (I did some substitution to make things simple):

    (1) use FindBin; (2) use lib $FindBin::Bin; (3) use dbPrjPath; ## company internal package (4) my $dir = dbPrjPath::prjPath(); #find project path (5) my $prog = $FindBin::Script; (6) exec("$prog @ARGV");

    above is the code. suppose code above is prog1. In line (4) a new project path is got. In this new project path there is a same script named prog1. The total code will get new project path and run the script in that path with the same script name "prog1" as line (6) indicates, i.e, runs B/prog1. This works well in original system, but in the other system, code in line (6) always runs A/prog1 so it is a infinite loop, which is a strange thing to me.

    In order to trace it, I insert a code as this between line (5) and (6) as (5.5) system("which $prog") and it shows B/prog1. I then inserted some debug info to make sure exec("$prog") runs itself. This confused me. so What happened? I confused...

      Could you reformat your post so that (long) code snippets do not mix with rest of the text? As it is, it is hard to make sense (of code). In case you missed the formatting tips mentioned before the textarea ...

      Use: <p> text here (a paragraph) </p> and: <code> code here </code> to format your post; it's "PerlMonks-approved HTML":
        thanks for your kind remind.

      Please post the values of $dir & $prog. Given those values, tell us where the command to be executed lives.

      (Nonetheless I will venture into mind reading) By the clue of $Script - basename of script ..., try executing the command with path prefixed as in ...

      ... $prog = join '/' , $dir , $prog; exec( $prog , ... );
Re^2: confused path
by parv (Priest) on Oct 09, 2012 at 09:00 UTC
    In what case would $prog1 be different if one instance is run by system() and other by exec()?
      I cannot imagine. But I cannot imagine how it were possible for which and exec, either.
      لսႽ ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ

        system("which $prog") would be passed through the shell. exec $prog would not be. The shell could run startup script which modify $PATH.

        perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'

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