From: Anupam Sengupta <anupamsg@...>
Date: 2007-06-27T11:55:09+09:00
Subject: Re: OS X reads builtin version of ruby


>>>>> "Richard" == Richard Lawrence <rwl@sas.upenn.edu> writes:

    Richard> The line Python installs in ~/.bash_profile seemed to be overriding
    Richard> the PATH setting in ~/.bash_login that the HiveLogic article
    Richard> advised.

    Richard> My solution was to move the Python line from .bash_profile, and
    Richard> include it in .bash_login.  I then deleted .bash_profile (or
    Richard> rather, moved it to .bash_profile.bad.) My .bash_login now looks
    Richard> like this:

You should move the contents of '.bash_login' to '.bashrc'

For an interactive login shell (like the one you see in OS X Terminal), when
bash starts up, it looks for the following files (in the order listed) and reads
only the FIRST file it finds (in your case, .bash_login, since you deleted
.bash_profile):

    1. ~/.bash_profile
    2. ~/.bash_login
    3. ~/.profile (this is mostly for Bourne Shell compatibility)

However, a non-login shell will ONLY read  ~/.bashrc

You can check this behavior by trying out the experiment listed at the bottom of
this post.

In order to ensure a consistent behavior (e.g. for the shells that you open via
Terminal.app and also for the ones that other applications such as BBEdit or
TextMate open for you), try the following:

1. Move the content of .bash_login to .bashrc
2. Delete .bash_login (after moving its contents)
3. Edit a new .bash_profile to have the following content:

   # Check for bash rc and source it. All changes to to that file.
   [[ -f ~/.bashrc ]] && . ~/.bashrc

   This line basically ensures that contents of .bashrc are also loaded when you
   have a normal login shell.

4. Quit Terminal.app and relaunch. Your PATH related changes should be
   effective.


    Richard> which seems to work like a charm.  I'm not all that knowledgeable
    Richard> about this stuff, though, so you may better off editing .bashrc, as
    Richard> Herbie advised.

The bash manual page at:

http://www.gnu.org/software/bash/manual/bashref.html#SEC65

has all the gory details which will help you here.

Another good and succinct article explaining the concept is:

http://jmatrix.net/dao/case/case.jsp?case=7F000001-1C208B0-10C91F4FD67-107

Hope this helps.

=================================== EXPERIMENT =================================

As an experiment, try this (first backup your existing files by renaming them to
something like .bash_login.bkp, .bash_profile.bkp and .bashrc.bkp):

Step 1: Create a single line .bash_profile with the content:

       echo "bash_profile was read"

Step 2: Create a single line .bashrc with the content:

       echo "bashrc was read"

Step 3: Ensure that you have renamed .bash_login and no such file exists in your
        home directory.

Step 4: Quit the Terminal.app and restart it again (or open a new Terminal
        Window). You should see this in the Terminal window:

       bash_profile was read

       This indicates that only bash_profile is read on an interactive login
       terminal.

Step 5: Now enter the following command to start another interactive (BUT
        non-login bash shell:

       <prompt> $ bash

       You should see the following:

       bashrc was read

This indicates that this time around, only .bashrc was read by the shell, since
it determined that it is *not* a login shell.

Step 6: Revert back all files from the .bkp versions you had created earlier.

===============================================================================

--
Anupam