SPUG: she-bang lines: "/usr/bin/perl" vs "/usr/bin/env perl"

Colin Meyer cmeyer at helvella.org
Sat Apr 14 15:14:53 PDT 2007

On Sat, Apr 14, 2007 at 12:45:33PM -0700, veritosproject at gmail.com wrote:
> Perl now has a ./Configure option that automatically symlinks
> /u/b/perl to /u/l/b/perl if you so choose.

... and thankfully, the default answer to that option is no, do not
create a symlink from /usr/bin/perl to where ever the perl executable
is installed (/usr/local/bin/perl by default). I've been bitten more
than once when configuring Perl with -des. Older versions used to create
that symlink by default.

Most unixy OSs rely heavily on their /usr/bin/perl, and so it is best to
leave it alone, and let the OS decide when to update it. If you upgrade
/usr/bin/perl, but the OS is relying on some bug or feature of the
version of Perl it installed into /usr/bin/perl, then stuff breaks. I
have witnessed troubles from upgrading Perl on Mac OSX and various linux
distros (at least debian and suse off the top of my head).

I go so far as never installing or upgrading any modules under


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