Getting "export PATH" to stick

Question

I just upgraded to Lion and I am using bash for the first time (my previous experience is with csh and tcsh). I have encountered unexpected behavior. A simple example is:

1. I create a file containing the following commands:

   echo PATH BEFORE is $PATH
   PATH=/usr/local/fortran:$PATH
   export PATH
   echo PATH AFTER is $PATH
   

2. I open a terminal (in bash) and execute the file shown above. It echoes the expected result:

   PATH BEFORE is /usr/bin: ...
   PATH AFTER is /usr/local/fortran:/usr/bin ...
   

3. I then type:

   echo $PATH
   

   and /usr/local/fortran is NOT part of the path. I assumed that the export command would make the PATH sticky. Can someone explain why this is not happening?

Answer 1

You need to source the file so that the exported variables are accessible to the current shell.

source script-file
echo $PATH

… or add the export command to one of bash's configuration files — In OS X, that'd typically be .bash_profile.

Answer 2

Put

PATH=/usr/local/fortran:$PATH
export PATH

in your .bash_profile file.

How do you execute the file containing the command ? Try sourceing it with source (man source)