In some environment, env doesn’t split arguments. So your env is looking for python -u in your path. We can use sh to work around. Replace your shebang with the following code lines and everything will be fine. #!/bin/sh ””exec python -u — “$0″ ${1+”$@”} # ”’ # vi: syntax=python p.s. we need not worry … Read more
If your script is intended for use by Node developers, you should absolutely just use #!/usr/bin/env node and not bother trying for compatibility with people who only have Node installed as nodejs. Rationale: It’s what the cool kids are doing, and if you don’t do it too, you’re not cool. Major node projects like jshint, … Read more
The shebang line has never been specified as part of POSIX, SUS, LSB or any other specification. AFAIK, it hasn’t even been properly documented. There is a rough consensus about what it does: take everything between the ! and the \n and exec it. The assumption is that everything between the ! and the \n … Read more
#!/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
It’s called a shebang, and tells the parent shell which interpreter should be used to execute the script. #!/bin/sh <——— bourne shell compatible script #!/usr/bin/perl <– perl script #!/usr/bin/php <— php script #!/bin/false <—— do-nothing script, because false returns immediately anyways. Most scripting languages tend to interpret a line starting with # as comment and … Read more
#!/usr/bin/env searches PATH for bash, and bash is not always in /bin, particularly on non-Linux systems. For example, on my OpenBSD system, it’s in /usr/local/bin, since it was installed as an optional package. If you are absolutely sure bash is in /bin and will always be, there’s no harm in putting it directly in your … 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 … 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
If you have several versions of Python installed, /usr/bin/env will ensure the interpreter used is the first one on your environment’s $PATH. The alternative would be to hardcode something like #!/usr/bin/python; that’s ok, but less flexible. In Unix, an executable file that’s meant to be interpreted can indicate what interpreter to use by having a … Read more