pip installs packages successfully, but executables are not found from the command line

I installed Python 2.7 and pip following these instructions, on Mac OS X v10.10.3 (Yosemite).

I can successfully install packages and import them inside my Python environment and Python scripts. However, any executable associated with a package that can be called from the command line in the terminal are not found.

For example, I tried to install a package called "rosdep" as instructed here. I can run sudo pip install -U rosdep which installs without errors and the corresponding files are located in /opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages. However, sudo rosdep init subsequently reports that the rosdep command is not found.

I even tried adding the above site-packages path to my $PATH, but the executables are still not found on the command line, even though the packages work perfectly from within python.

Why does this happen, and how can I fix it?

_{See also: Unable to import a module that is definitely installed - these two problems often have the same root cause.}

Solution

Check your $PATH environment variable.

tox has a command line mode:

$ pip list | grep tox
tox (2.3.1)

Where is it?

(The 2.7 stuff doesn't matter much here, sub in any 3.x and pip's behaving pretty much the same way)

$ which tox
/opt/local/Library/Frameworks/Python.framework/Versions/2.7/bin/tox

And what's in my $PATH?

$ echo $PATH
/opt/chefdk/bin:/opt/chefdk/embedded/bin:/opt/local/bin:..../opt/local/Library/Frameworks/Python.framework/Versions/2.7/bin...

Notice the /opt/local/Library/Frameworks/Python.framework/Versions/2.7/bin? That's what allows finding my pip-installed stuff

Now, to see where things are from Python, try doing this (substitute rosdep for tox).

$python
>>> import tox
>>> tox.__file__

that prints out:

'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/tox/__init__.pyc'

Now, cd to the directory right above lib in the above. Do you see a bin directory? Do you see rosdep in that bin? If so, try adding the bin to your $PATH.

$ cd /opt/local/Library/Frameworks/Python.framework/Versions/2.7
$ ls -1

Output:

Headers
Python
Resources
bin
include
lib
man
share