〉help commands gargle
Help pages from external command gargle:
No manual entry for gargle
Error: 
  × std::help::command_not_found
   ╭─[entry #205:1:1]
 1 │ help commands gargle
   ·               ───┬──
   ·                  ╰── command not found
   ╰────

export def "help commands" [
    ...command: string@"nu-complete list-commands"  # the name of command to get help on
    --find (-f): string  # string to find in command names and usage
] {
    let commands = ($nu.scope.commands | where not is_extern | reject is_extern | sort-by name )

    let target = ($command | str join " ")  # don't shadow `command` parameter, we want to use it later...

    if not ($find | is-empty) {
        # TODO: impl find for external commands
        let found_commands = ($commands | find $find --columns [name usage search_terms])

        if ($found_commands | length) == 1 {
            show-command ($found_commands | get 0)
        } else {
            $found_commands | select name category usage signatures search_terms
        }
    } else if not ($command | is-empty) {
        let found_commands = ($commands | where name == $target)

        if not ($found_commands | is-empty) {
            show-command ($found_commands | get 0)
        } else {
            try {
                print $"(ansi default_italic)Help pages from external command ($target | pretty-cmd):(ansi reset)"
                 ^($env.NU_HELPER? | default "man") $command
            } catch {
                command-not-found-error (metadata $command | get span)
            }
        }

    } else {
        $commands | select name category usage signatures search_terms
    }
}