#!/usr/bin/env node is an instance of a shebang line: the very first line in an executable plain-text file on Unix-like platforms that tells the system what interpreter to pass that file to for execution, via the command line following the magic #! prefix (called shebang). Note: Windows does not support shebang lines, so they’re effectively … Read more
Running a command through /usr/bin/env has the benefit of looking for whatever the default version of the program is in your current environment. This way, you don’t have to look for it in a specific place on the system, as those paths may be in different locations on different systems. As long as it’s in your path, it … Read more
Generally, take care of some pitfalls: set the executable flag on the script: chmod u+x test.py try to execute with a preceding dot “./”, so call ./test.py otherwise it might execute some other script from within your PATH also make sure you don’t have windows line endings, this seems to prevent the shebang evaluation, too. There are some suggestions around, e.g. in this answer, on … Read more
It’s called a shebang, and tells the parent shell which interpreter should be used to execute the script. Most scripting languages tend to interpret a line starting with # as comment and will ignore the following !/usr/bin/whatever portion, which might otherwise cause a syntax error in the interpreted language.
is more portable because in general the program /usr/bin/env can be used to “activate” the desired command without full path. Otherwise, you would have to specify the full path of the Python interpreter, which can vary. So no matter if the Python interpreter was in /usr/bin/python or in /usr/local/bin/python or in your home directory, using #!/usr/bin/env python will work.
I see this at the top of Python files: For Python 2 files#!/usr/bin/env python For Python 3 files#!/usr/bin/env python3 It seems to me like the files run the same without that line.
I see this at the top of Python files: For Python 2 files#!/usr/bin/env python For Python 3 files#!/usr/bin/env python3 It seems to me like the files run the same without that line.
The shebang line in any script determines the script’s ability to be executed like a standalone executable without typing python beforehand in the terminal or when double clicking it in a file manager (when configured properly). It isn’t necessary but generally put there so when someone sees the file opened in an editor, they immediately … Read more
It’s a convention so the *nix shell knows what kind of interpreter to run. For example, older flavors of ATT defaulted to sh (the Bourne shell), while older versions of BSD defaulted to csh (the C shell). Even today (where most systems run bash, the “Bourne Again Shell”), scripts can be in bash, python, perl, … Read more
The shebang line in any script determines the script’s ability to be executed like a standalone executable without typing python beforehand in the terminal or when double clicking it in a file manager (when configured properly). It isn’t necessary but generally put there so when someone sees the file opened in an editor, they immediately … Read more