How to implement a script interpreter in shell on Mac OS X?

Question

I'm trying to implement, in shell, a script interpreter that I can use in a shebang line. For example, here is my interpreter and a test script using that interpreter:

-----
$ cat interp
#! /usr/bin/env bash

printf "interp called with args: %s\n" "$*"

-----
$ cat test
#! ./interp

printf "test script!\n"

When I run ./test on a Linux system, interp is called with the arguments that I expect:

$ ./test -a
interp called with args: ./test -a

But when I do the same on Mac OS X 10.8.4, I get the following result:

$ ./test -a
test script!

The contents of the test script are being executed by bash, rather than the interp script being executed with the test file as the first argument.

Am I doing this correctly and such a thing simply won't work on Mac OS X? Or is there a better way to accomplish this?

Works as expected with zsh on OSX 10.6.8, but not with the macports bash. — Rufty
– Rufty, Commented Jul 28, 2014 at 14:08
Mac OS X requires the program named in the shebang to be a binary executable, not a script, AFAICR. The workaround anubhava suggests runs /usr/bin/env (a binary executable) and requests it to run your script. — Jonathan Leffler
– Jonathan Leffler, Commented Jul 28, 2014 at 14:14

anubhava · Accepted Answer · 2014-07-28 14:06:31Z

2

Yes there is a way to make it work on OSX, which is same as what you did in your first script i.e. by using /usr/bin/env.

Have ./test as:

#!/usr/bin/env ./interp

printf "test script!\n"

answered Jul 28, 2014 at 14:06

anubhava

790k67 gold badges603 silver badges671 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Patrick Over a year ago

This does work, than you. Any idea why my first attempt did not work? (It also fails if I use absolute path rather than #! ./interp)

anubhava Over a year ago

Yes it doesn't work with full path to interp also on OSX. I am still researching why OSX needs /usr/bin/env but Linux doesn't. I will update once I find something.

Neera Saxena · Accepted Answer · 2017-08-22 10:16:03Z

-1

OS X is built on top of UNIX. The application Terminal takes you from the outer world of OS X to the inner world of UNIX. Terminal is located in the Utilities folder inside the Applications folder. To open Terminal, double-click the Terminal icon, and you see a window like the one shown in the figure.

answered Aug 22, 2017 at 10:16

Neera Saxena

1

Collectives™ on Stack Overflow

How to implement a script interpreter in shell on Mac OS X?

2 Answers 2

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related