Making Shebangs Portable – Using env
Of course, if you write a script with a Shebang on your machine, it may not work on other machines. For instance, another person may not have Python installed. Also, another person may not have Python installed in the same location. So how do we make the Shebang portable?
First, remember to use specific executable names. For instance, instead of using /usr/bin/python, consider using /usr/bin/python3 in the Shebang. Some Ubuntu versions have Python 3 installed, but the interpreter is named python3 instead of python.
Another important tip is to use the env command. The env command is a part of the Linux System Base, which is a list of programs that have to be present in a system for it to be called a Linux OS. Ubuntu, Fedora, Manjaro, CentOS, RHEL, etc. machines all carry the env command.
Used on its own, env simply lists all available commands. But if you give env an argument which is the name of an installed interpreter (such as python3), it will identify the correct location of the interpreter on its own. Plus, env itself is always located in the same place on all Linux machines:
/usr/bin/env
So you can use env to make your shebangs portable:
For Python:
#!/usr/bin/env python3
For Node-JS (if the script is in Javascript):
#!/usr/bin/env node
For Perl:
#!/usr/bin/env perl
Using Shebang in Linux
Imagine you’re working on a Linux computer and have a recipe with instructions written in different languages. But your computer only understands English! That’s where the shebang comes in. It’s like a tiny label at the beginning of the recipe that tells your computer which “translator” to use for each language. This magic symbol, #!
, followed by the interpreter’s path, is the key to understanding and running all sorts of scripts on your system.