How can I create something similar to an alias, that does properly expand to the initial command?

Question

I have set up aliases for apt-get update, apt-get install, and so on. Thats quite convenient. But what I really would like to have is something like this:

type agi TAB vi and have it automatically list all packages starting with vi, as it would happen when issuing apt-get install TAB vi.

Would something like this be achievable somehow, maybe by writing a little script?

Answer 1

Bash programmable completion is something I haven't bothered much with myself, but I believe this will do what you want (NB assumes bash version 4.0 or newer. If you run Ubuntu 10.04 or newer, you're good.):

alias agi='apt-get install'
_agi_completion() { 
    mapfile -t COMPREPLY < <(apt-cache --no-generate pkgnames "${COMP_WORDS[COMP_CWORD]}")
}
complete -F _agi_completion agi

Programmable Completion in bash's manual explains how it works, though it's quite complex.

Answer 2

You need to add your aliases to the shell completion dictionaries so it knows what it is completing for those commands. The shell completions should already be named functions, but you have to tell it that they apply to your new command names.