How to pipe the list of commands displayed by of “tab complete”?

Question

When using commands in bash I like the double tab option to display the available commands. Some commands have more possible matches than others:

Is there a way I can pipe the output of the double tab to somwehere, like grep? I found a related post, but I'm still not sure how to implement it to pipe it to grep.

Answer 1

For commands use compgen -c:

$ compgen -c bas
basename
base64
bashbug
bash
basename
base64
bashbug

This output you can simply pipe through grep.

Answer 2

Based on @salutis's answer I created a script which I called comp and stored in ~/bin/comp that searches commands', aliases, and builtins, (option flag -cab see the bash man entry), with an optional second parameter which, if present, pipes the output to grep and searches for the second parameter.

Usage: comp string [keyword-for-grep]

Code:

#!/bin/bash

if [ -z "$1" ]; then
    echo usage: comp string [keyword-for-grep]
    echo 
    exit
fi

if [ -z "$2" ]; then
    compgen -cab -- $1
    exit
fi

compgen -cab -- $1 | grep -i $2

Personally I would also be interested in figuring out a way to remove the last command from the shell history in the script (something related to history -d) so that when searching bash history I won't find comp entries. I know I can also do this with HISTIGNORE but linux is pretty powerful so there must be a way to do it from the script file, too - right?

Answer 3

Why not find what you are looking for?

Example:

find / -name ec2* -executable -type f -perm -og+rx -print

Knowing your use case I can create a more detailed command example.