On Sun, Sep 01, 2019 at 03:22:32PM -0400, Lee wrote:
[...]
> You have to source the script instead of running it.
Yes, exactly.
> I'm not entirely clear about a new shell gets it's own env that
> disappears when the shell exits thing, but try this:
It's not only a shell thing. It's a basic Unix process thing:
child processes inherit (well, almost always) their parent's
environment -- more precisely a copy of it. They can change
their copy, but not the parent's. That's by design: lots of
loosely coupled programs calling each other (and that's what
Unix is, after all ;-) would degenerate into an unmaintainable
mess otherwise...
> $ cat setps1
> ##!/bin/bash
> # can i change ps1 from a script?
> echo "FOO = ${FOO}"
> export FOO=BAR
> echo "FOO now = ${FOO}"
> export PS1='\[\e]0;\u@\h:
> \w\a\]${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w
> #\[\033[91m\] '
>
> $ export FOO=FOO
> $ ./setps1
> FOO = FOO
> FOO now = BAR
> $ echo $FOO
> FOO
>
> See? FOO is back to it's pre ./setps1 value
>
> Now try
> $ source setps1
That's the way. There's a shorthand for "source", which is ".". So instead
of doing
source setps1
you can say
. setps1
Cheers
-- tomás
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