bind: warning: line editing not enabled

The other day I was writing a Makefile which involved nvm and stumbled upon an error that seemed to make sense, on one hand, but on the other hand I couldn’t quickly google out a clean solution. Digging in some more, I’ve devised my own, which I’m going to present here. 🤓

As I’ve mentioned before, for every new project that I get on, as part of the onboarding I write a Makefile for the stuff I’ll need to run frequently, so that I can make use my muscle memory instead of trying to brute-forcefully remember them.

So I needed to run something like nvm exec 9.11.1 yarn test, which is tricky because nvm is implemented as a shell function which is defined when a login shell is initialized, and so can’t directly be called from a script. One way to get that is this:

test:
	bash --login -c 'nvm exec 9.11.1 yarn test'

And it worked, except that there was a warning that pointed to a line in ~/.bashrc.my where I was defining a custom Bash key-binding with bind:

/Users/vlad/.bashrc.my: line 277: bind: warning: line editing not enabled

OK, makes sense: this is not a real login shell, and because of that bind complains. There should be a way to detect that and skip bind calls in that case. After a few sporadic rounds of disappointing “let’s google this quickly”, I went to The Source® with the intention to find out The Right Way® to do this.

Essentially I needed to write a is_interactive_shell function, and although the implementation is not exactly straightforward, it’s still much nicer than what I’ve been able to find so far:

function is_interactive_shell() {
	# https://www.gnu.org/software/bash/manual/html_node/Is-this-Shell-Interactive_003f.html
	[[ "$-" =~ "i" ]]
}

…and now I can say:

if is_interactive_shell; then
	# fzf git branch name; use like this: git checkout ^g^b
	bind '"\C-g\C-b": "$(git branch -a | cut -c 3- | fzf)\e\C-e"'
fi

Nice and clear! 👍

* * *

PS: I later found out that I could get away with something like this:

source ~/.nvm/nvm.sh && nvm exec ...

…which would have prevented the warning altogether, 😆 but it’s still useful to understand the warning and how to work around it. 🤓