Run python function in shell script

Question

Let's say I want to use a shell script to run a python file, called test.py, which is in a directory called Test in my home directory. I tried the following code, which does not work:

 #!/bin/bash
 echo "Starting."
 module load gcc/4.8.2
 module load python/3.4.1
 echo "Modules loaded."
 $HOME/Test/test.py
 exit 0

I do not believe that how I am trying to run the program ($HOME/Test/test.py) works. I have not been able to determine how to do this, despite searching for a long time. Any help would be appreciated.

Answer 1

This is likely one of the following, or it may be a combination of both.

The python script is not executable. Fix with:

chmod u+x $HOME/Test/test.py

The script does not start with a #! line pointing to python. Fix that by making this the first line of test.py:

#!/usr/bin/env python

You can also use a full path instead of using /usr/bin/env to use $PATH to resolve the name.

#!/usr/local/bin/python

• Alexander Whatley: Thanks, after adding "chmod u+x $HOME/Test/test.py" to my program, it created an output file, but it did not include the output of test.py (which simply prints "Hello World"). Am I missing something else? I am using python 3.4.1, so do I need to write "#!/usr/bin/env python3" instead?
• Dan Lowe: /usr/bin/env will just resolve whatever is after it to some full path, so if you use python as python3, then yes you would do that. You can also use a full path to the interpreter instead, such as #!/usr/bin/python3.