Turn an application or script into a shell command

Question

When I want to run my python applications from commandline (under ubuntu) I have to be in the directory where is the source code app.py and run the application with command
<

Answer 1

Probably you want to symlink to your file location instead of adding another location to the path

chmod +x app.py
ln ~app.py /opt/local/bin/app

...assuming that /opt/local/bin is already in your path,.

Also, do not forget to add the shebang line to the first line of your script: #!/usr/bin/env python