How do I find out where paths in my $PATH were defined?

Question

There are some paths in $PATH, which I don't want. I'm not sure how they got there; they aren't coming from my .profile. Is there a way to determine which scripts are modifying $PATH?

Answer 1

The very first file to processed is /etc/profile. At the beginning of this file, add the line

set -x

then open a new terminal window. You will get more output than you wanted, but it will be a trace of all the bash code that is executed from your startup scripts.

Answer 2

In OS X, default paths are set in /etc/paths, and possibly in the sub-files (if any) of /etc/paths.d/. See also path_helper(8).