What does the - option to env do?

Question

From the man page for env:

The historic - option has been deprecated but is still supported in this implementation.

What does the "historic - option" do?

In particular, why does it change which version of python is run?

~:$ env python
Python 2.6.5 Stackless 3.1b3 060516 (release26-maint, Mar 24 2010, 09:47:07)

but:

~:$ env - python
Python 2.5.1 (r251:54863, Feb  6 2009, 19:02:12)

score 1 · Answer 1 · answered May 15 '10 at 16:43

1

"Historic"? That's a new one. Here's an excerpt from the GNU coreutils 7.6 env(1) man page:

  -i, --ignore-environment
          start with an empty environment

....

  A mere - implies -i.  If no COMMAND, print the resulting environment.

Pass no command and see if there's a change in $PATH.

answered May 15 '10 at 16:43

ah, so it seems a way to run something with no environment pre-set... i don't know off the top of my head how that will be handy, but i am going to find a use for it one day. +1 – cpbills May 15 '10 at 16:59
@cpbills: It's good for dealing with `$LD_*`. – Ignacio Vazquez-Abrams May 15 '10 at 17:04

1 Answers1