Dynamic options based on the environment

Imagine that you want to executes some documents/source codes but want to skip some of them if you are running in, let’s say, MacOS.

You could do something like this:

$ cat test/ds/for-mac.args
-l=python,shell
--skip
byexample/prof.py
docs/overview/good-practices.md
--
byexample/*.py
docs/overview/*.md

$ cat test/ds/for-linux.args
-l=python,shell
--
byexample/*.py
docs/overview/*.md

$ if [ "$(uname)" = "Darwin" ]; then
>   byexample @test/ds/for-mac.args
> else
>   byexample @test/ds/for-linux.args
> fi

Indeed $(uname) will return "Darwin" on MacOS and yes, byexample then will be executed with the additional arguments from test/ds/for-mac.args.

But if your skills with shell scripting are a little rusted, or you have a much complicated situation that depends on a lot on the environment, you may want to try something else.

Consider test/ds/for-mac.args and test/ds/for-linux.args, they are quite similar and only differ but just a little.

You could use a templating system to generate the argument file from a template:

$ cat test/ds/template.args
-l=python,shell

--
byexample/*.py
docs/overview/*.md

Then:

$ osname=$(uname) j2 test/ds/template.args > test/ds/good.args
$ byexample @test/ds/good.args

j2 is one of many engines based on Jinja2. I used kolypto/j2cli but other implementations exist like mattrobenolt/jinja2-cli.

Of course, using a template engine is just an idea. See if it helps you!!