So if I understand you correctly, if the line
#!/usr/bin/perl
exists in your Perl program, then that Perl is used regardless.
And if it is missing, then
perl -e myperl
will use the first Perl environment that is found in the environment $PATH.
> Anthony (Tony) Esposito
> Senior Technical Consultant
> Inovis(tm), formerly Harbinger and Extricity
> 2425 N. Central Expressway, Suite 900
> Richardson, TX 75080
> (972) 643-3115
> [EMAIL PROTECTED]
>
-----Original Message-----
From: Bob Showalter [mailto:[EMAIL PROTECTED]
Sent: Wednesday, April 02, 2003 12:29 PM
To: Tony Esposito; [EMAIL PROTECTED]
Subject: RE: Which Perl is used to run the script???
Tony Esposito wrote:
> Question:
>
> When a Perl script - let's say myperl.pl - has the following as its
> first line:
>
> #!/usr/bin/perl
>
> yet your PATH is set to use another version of Perl - let's say
> /opt/perl5.6.1/bin/perl -
>
> then which 'Perl' is used when you execute the program from the
> command line like so:
>
> /opt/perl5.6.1/bin/perl -e myperl.pl
(You wouldn't use -e here)
This will run the script using the /opt/perl5.6.1/perl binary. The
executable in the #! line is ignored. (But options on that line, like -w
_are_ processed.)
>
> and which is used when you execute the program from the command line
> like so:
>
> myperl.pl
The kernel searches your PATH for myperl.pl. It then sees the #! line in
that script and passes the script to that specific executable.
>
> In other words, which 'Perl' takes precedence or how does the
> precedence work?
Normally, you will install Perl to some location appropriate to your
architecture (e.g. /usr/local/bin for BSD-ish systems) and then link
/usr/bin/perl to the executable you would like to run by default. Then it is
customary to use #!/usr/bin/perl in your scripts. If you want to switch
your "default" version, you just adjust the link /usr/bin/perl to point to
another version, and you don't need to change your scripts.
It is also customary to add the perl bin directory to your PATH, so you can
find the various supporting utilities that come with perl, such as perldoc.
Note that when you "make install" with perl, the #! lines in the supporting
utilties like perldoc will point to the specific version you are installing
and _not_ to /usr/bin/perl. This makes sure that the supporting utilities
run with the version of perl they were installed with.
HTH
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