UNIX for Dummies Questions & Answers

Hi - I am trying to include the MSQ.exe that I have downloaded for the sake of learning. My current /.bash_profile file reads:


PATH=/Library/Frameworks/Python.framework/Versions/3.1/bin:/Applications/XAMPP/xamppfiles/bin:$PATH
export PATH

-----------------------------------

interestingly, another file, /etc/paths reads:

/usr/bin
/bin
/usr/sbin
/sbin
/usr/local/bin

-----------------------------------


at the prompt, if I$ echo $PATH I get


/Library/Frameworks/Python.framework/Versions/3.1/bin:/Applications/XAMPP/xamppfiles/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin


almost a combination of the two minus the /usr/X11/bin.


What must I do to include all of the $PATH variable into either /.bash_profile or /etc/paths? Which one do I put it in? Which ever one it is, that is where I will put the path the the MSQ.exe file.

Lastly, what is telling the OS where to find the $PATH variable in the first place? It seems like there must be some instruction that is causing the OS to look in those two different places.

---------- Post updated at 04:43 AM ---------- Previous update was at 04:41 AM ----------

Thanks for any and all help on this!

Is OS specific...

But generally in UNIX you would have a default profile in /etc which is read first, so you would set here at a minimum for all purpose except administration stuff and customize the extra needs in the users $HOME/.profile

Since you did not give your OS, there is not much more to say...

Thanks! My OS is Mac OSX 10.6. Thanks for explaining where I need to put the path to the MSQ.exe.

Interestingly, on another computer with Mac OSX 10.5 if I

$ echo $PATH

I get:

[stuff in /.profile]:[stuff in /etc/paths]:[stuff in a third location]

I guess I am not understanding what is controlling the OS to look in these three locations once again to determine the collective path. Thanks.

It's not one giant thing. Anything can and does set it, and passes on copies of these changes to whatever it creates in turn. To get a complete understanding of how this PATH is set you'd need to know everything that changed it from the point your system runs init until the point your window manager creates your shell -- anything along the way between those two can affect PATH.

Only after all that happens, does your shell exist to start changing it too...

1) Your window manager creates a shell prompt. What PATH does your window manager have? Who knows. Whatever it had for whatever reason, your shell gets a copy.
2) shell reads /etc/profile. This is a script -- they can do anything they want in there, like read other files, set a special path for root only, or anything else you can imagine.
3) shell reads ~/.bashrc. This is also a script.

Thank you, Corona688. I think your explanation covered every base I could expect to find in such a complicated concept. I will have to woodshed a bit at this point to truly understand what you said. Because you pointed me in the right directions as far as what to look at as well as the concept behind a very dynamic path variable, I will be able to eventually understand. Thanks!

---------- Post updated at 06:14 PM ---------- Previous update was at 05:57 PM ----------

Edit: I found what seems to be a comprehensive explanation of how PATH is constructed, at least in MAC OSX 10.5 and up. This link below explains that a script called path_helper located in /etc/profile looks at text files in /etc to construct the PATH and MANPATH variables.


softec.lu/site/DevelopersCorner/MasteringThePathHelper