Calling alias with other alias + parameters

Question

i was trying to summerise grep while being able to give another command with parameters but I cannot figure out how to make it work What I am doing is this

alias pac='sudo pacman'

grp(){
     $1 | grep $2 | less
}

And trying to run any of these:

grp 'pac -Q' nvidia
grp "pac -Q" nvidia
grp (pac -Q) nvidia

but i am failing in everyone of them,any advice?

TL;DR: Basically the tittle or Trying to make command -XYZ acceptable as an $NUM value or any other form usable the same way

Answer 1

There might be a workaround. In bash, when an alias expansion ends with a space, the next word is also considered for expansion. So if I had:

alias foo='echo ' bar=hello

Then foo bar would result in echo hello being run:

$ foo bar
hello

With this, you can use an alias for the grp function to have its first argument be considered for alias expansion, and then modify grp accordingly to use the last argument as the pattern:

grp () {
  local pat="${@: -1}"
  "${@:1:$#-1}" | grep "$pat" | less
}
alias grp='grp '

Then:

$ grp pac -Q nvidia
lib32-nvidia-utils 440.82-1
nvidia-dkms 440.82-2
nvidia-settings 440.82-1
nvidia-utils 440.82-2
opencl-nvidia 440.82-2

Of course, this won't work with complex aliases, for example those that use pipelines:

$ alias foo='bar | cat'
$ grp foo nvidia
cat: nvidia: No such file or directory

Answer 2

You might try:

grp() {
    local grep_pattern=$1
    shift
    # remaining args are the command:
    "$@" | grep "$grep_pattern" | less
}

And invoke it like:

grp nvidia pac -Q

Answer 3

EDIT: I dun goofed. Nevermind.

A little old I know, but assuming you don't need to be widely portable across various older shell implementations, process substitution (instead of pipes) is one way to do this directly.

grp() {
  less -f <( grep ${@:2} <( $1 ))
}

invoke as grp 'pac -Q' nvidia, as requested.