make ignores my python bash alias

Question

My CentOS 5.5 server has both Python 2.4 and Python 2.7 installed (to /opt/python2.7.2). In my ~/.bash_profile I have two aliases pointing to my Python 2.7 install and my PATH configured as:

alias python=/opt/python2.7.2/bin/python
alias python2.7=/opt/python2.7.2/bin/python
PATH=$PATH:/opt/python2.7/bin

There's also a symbolic link I created as well:

ln -sf /opt/python2.7.2/bin/python /usr/bin/python2.7

I have a Makefile which has the following lines:

pythonbuild:
        python setup.py build

To my surprise I found that Python 2.4 is being invoked and not Python 2.7.

I have to explicitly specify python2.7:

pythonbuild:
        python2.7 setup.py build

Are bash aliases ignored by make? I am guessing make uses PATH to locate the first python executable (which happens to be Python 2.4) instead?

Answer 1

From bash(1):

   Aliases are not expanded when the shell is not interactive,
   unless the expand_aliases shell option is set using shopt
   (see the description of shopt under SHELL BUILTIN COMMANDS
   below).

While you might be able to use something like SHELL=/bin/bash -O expand_aliases in your Makefile, I think keeping an explicit dependency upon the newer Python in your Makefile is much better than keeping the dependency hidden in your user ~/.bash_profile file.

Instead, put PYTHON=/opt/python2.7/bin/python into your Makefile, and then you can just use:

pythonbuild:
    $(PYTHON) setup.py build

in your rules.

The best part is you can easily change which Python interpreter you use on the command line:

make PYTHON=/tmp/python-beta/bin/python pythonbuild

If you deploy it to another site, it is just one line in the Makefile that needs to be updated.

Answer 2

aliases are typically just used by interactive shells

Note only that, I think that make does not always invoke the shell Your best bet is to be explicit about the paths you want to use

Answer 3

Workaround with grep and awk:

The advantage of this solution is that if I change the alias in the ~/.bash_profil or ~/.bashrc, it is automatically adopted by my makefile as well.

Description:

I want to use the alias lcw in my makefile, which is defined like in my ~/.bashrc file.

.bashrc

...
alias lcw='/mnt/disk7/LCW/productiveVersion/lcw.out'
...

I use also the definition of a varialble as presented in the other solutions, but I directly read its value from the bashrc by using grep and awk.

makefile

LCW= $(shell grep alias\ lcw= ~/.bashrc | awk -F"'" '{print $$2}')

.PHONY: std
std:
    $(LCW)

As you see the lcw alias is called by the command $(LCW) from the makefile.

Note:

My solution assumes that the alias in the bashrc is defined within ' ' characters.