Provide utility environment variables to `meta-exec`

[vviikk]

🚀 Feature Proposal

Have things like current folder name (just the name, not the full path) as an environment variable you can use in commands

Motivation

Take this for example. I have three repos (two python repos & one node)

And I run the following command:

$ meta exec "[ -f requirements.txt ] && echo dir:`pwd`" --include-only=python-project-1,python-project-2,node-project-2

The context or current working directory is still where I ran the command from. It would be good to have access to such things when running meta-exec. But I don't know if this should be in loop or meta-exec. An environment variable like META_CWD. See example below.

Example

Say I want to create virtual environments for all my python projects with just the folder name as the venv name.

$ meta exec "[ -f requirements.txt ] && python3 -m venv --prompt $META_CWD   .venv"

Currently there is no easy way to do this so I just manually create my virtual environments. Hope I am making sense.

[patrickleet]

Makes sense

try xargs though

meta exec "pwd | xargs basename | xargs echo"

for venv

meta exec "pwd | xargs basename | xargs python3 -m venv .venv --prompt"

For example:

meta exec "pwd | xargs basename | xargs python3 -m venv .venv --prompt" --include-only=plugins/meta-loop

[vviikk]

What manner of sorcery is this? And why does this work lol?!

[patrickleet]

You were having trouble with when the expression is run - the command pwd always worked directly.

Seems that when you use in as an expression, wrapped in ` or $(), it gets evaluated before being executed in each directory.

So, in this example, pwd returns the directory path.. then it is piped to xargs which, as a simple explanation, basically puts it as an argument to the given command..

basename gets the directory name, and the result of that is piped to the next xargs command.

[patrickleet]

I didn't try this before, but escaping the `'s also works:

➜  meta exec "echo `pwd`" --include-only=plugins/meta-loop

plugins/meta-loop:
/Users/patrickleet/dev/mateodelnorte/meta
plugins/meta-loop ✓

➜  meta exec "echo \`pwd\`" --include-only=plugins/meta-loop

plugins/meta-loop:
/Users/patrickleet/dev/mateodelnorte/meta/plugins/meta-loop
plugins/meta-loop ✓

➜  meta exec "echo \$(pwd)" --include-only=plugins/meta-loop 

plugins/meta-loop:
/Users/patrickleet/dev/mateodelnorte/meta/plugins/meta-loop
plugins/meta-loop ✓

[patrickleet]

I added a note to the README: https://github.com/mateodelnorte/meta#how-to-escape-expressions

[vviikk]

Legend, thanks.