I'm on my phone so I'm too lazy to dig for this, but I'm pretty sure they're talking about the bit of shell script that gets run if you type a command that isn't found in PATH.

Fedora and Debian will both dive straight into searching apt/dnf for a matching package and ask "do you want to install this?"

I imagine you could create a hook that gets run for any command failure, but again I'm on my phone so not sure.

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VorpalWay 11 hours ago | parent | next [-]

This is generally called a command-not-found handler and are a feature of all the major shells (though the exact details differ, the general idea is to define a function with a specific reserved name), and most majors distros have ones that can be installed, even if they aren't by default.

I wrote my own (much faster) such handler for Arch Linux. I even wrote a blog post about the design: https://vorpal.se/posts/2025/mar/25/filkoll-the-fastest-comm...

	▲	zahlman 4 hours ago \| parent [-]
		I thought of that, but TFA describes a system that trips on incorrect filenames rather than just incorrect commands.

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dataflow 11 hours ago | parent | prev | next [-]

It's https://packages.debian.org/sid/command-not-found

	▲	ktm5j 11 hours ago \| parent [-]
		which is run by bash in the way I described. In /etc/bash.bashrc: # if the command-not-found package is installed, use it if [ -x /usr/lib/command-not-found -o -x /usr/share/command-not-found/command-not-found ]; then ... fi

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aflag 11 hours ago | parent | prev | next [-]

I thought Ubuntu did that, but not Debian. Still, that's very different than what the author mentioned

	▲	ktm5j 11 hours ago \| parent [-]
		Oh you might be right about Ubuntu vs Debian.. but I'm right about everything else I said. I went and looked at the source code.

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bandrami 4 hours ago | parent | prev [-]

cachy's setup of fish tries to suggest commands (and even arguments) it might be, which I find terrifying and so turn off.