[sf-perl] dynamic #! line

Chris Weyl cweyl at alumni.drew.edu
Tue Mar 24 12:28:14 PDT 2009

On Mon, Mar 23, 2009 at 5:48 PM, Matthew Lanier <matt at lanier.org> wrote:

> long story, i'm trying to not modify the startup context if i don't need
> to.
> as dfetter suggested, '/usr/bin/env perl' works, though it appears to work
> via perl being in the path.

On some boxes at $work, we have very old or otherwise wonky Perl
installations as the system Perl.  I've built and installed a newer Perl on
these boxes; to use the new Perl transparently I created a small module that
checks $^X to see what's currently executing the script.  If it's the old
system Perl and the new Perl is available, we exec ourself under the new
Perl; if we're running under the new Perl (or it's unavailable), it's a

This works nicely as it's use'd, and so gets run nice and early.  I'd
imagine if you had to, you could rig it to reexec with more command-line

Chris Weyl
Ex astris, scientia
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