I think your best bet to to create a script called help and run “help <command>” and the script would do the rest.

#!/bin/bash

export PAGER="less -r"
export GROFF_NO_SGR=1
export LESS_TERMCAP_mb=$'\E[01;31m'
export LESS_TERMCAP_md=$'\E[01;31m'
export LESS_TERMCAP_me=$'\E[0m'
export LESS_TERMCAP_se=$'\E[0m'
export LESS_TERMCAP_so=$'\E[01;44;33m'
export LESS_TERMCAP_ue=$'\E[0m'
export LESS_TERMCAP_us=$'\E[01;32m'

man ls

Grep?

To answer the original question, even though @RedWeasel@lemmy.world’s advice really is superior:

All commands that can be executed via your shell must live in your $PATH or their subdirectories. You could enumerate all files in there, filter by being executable, and run them with the –help argument.

You can then filter these commands by their exit code. If –help is a recognized flag, the exit code should be 0. Otherwise it should be something else. (Running every command blindly might be a bad idea though.)

There’s no particularly smart way to accomplish this in the exact way that you want. I don’t like the solution which searches your $PATH because now you’re adding latency to search your entire $PATH for every command to add this functionality. It’s a singularly better solution to tell the CLI what you want versus the CLI attempting (using logic) to figure it out.

The easiest solution here is to create your own command which calls the target application with –help;

#!/bin/bash
$1 --help | bat --language=help

Then run it;

$ script_name docker

and it will run docker --help | bat --language=help. If you use this solution a lot you can try to use bash function which you call at the end of commands if they error;

helpfunc() {
  $1 --help | bat --language=help
}

trap 'helpfunc' ERR

But now you have to run logic to truncate previous commands to only return the first word of a command from history and it becomes a real PITA…

Long story short, if you want to hack your console experience like this, you’re looking for a functional shell scripting language, like Elvish shell and not bash.

cd into the directory you want to test commands.

bash

for i in ls

do

$i --help >/dev/null 2>&1 && echo $i

done

any command which honors a --help will get listed. I suppose you could add a >> /tmp/output after the echo $i to log it. run it in /bin, /usr/bin, usr/local/bin

ah …and that ls in the commands listed above is a backtick ls backtick. backtick is the key in the upper left hand corner of the keyboard which shares a key with ~