Simple AUR helper for Arch Linux

aur.sh

#!/usr/bin/env bash

# AUR helper, similar to that of paru or yay, but far simpler and written in bash.
# This is better for a few reasons:
#   - No pacman-esque syntax (-S)
#       This is unneeded as pacman can handle all except for installation of AUR
#       packages, such as sync, query, etc.
#   - No compile-time dependencies (rather, no compilation at all)
#       Paru and yay require Rust and Golang respectively -- requiring hundreds of MiB
#       of code to be installed and immediately deleted once the helper package is built.

# Update 2/16/22: Add --noconfirm to makepkg invocation
# Update 5/26/23: Move shebang to line 1 (thanks ChillerDragon)

# Print syntax when no arguments are provided / --help is given
function help {
    printf "Syntax:\n    aur [arg1], [arg2]... - Download packages\n    aur --help - Show this page\n"
    exit
}

# Ensure user & their environment meet the necessary conditions for package installation
function check {
    # If user doesn't have write priviliges:
    if [ ! -w `pwd` ]
    then
        printf "You do not have write privilages.\n"
        exit
    fi
    # If package's interim path already exists in the form of a non-empty file or directory:
    if [ -s ./$1 ]
    then
        printf "Destination path already exists and is not empty.\n"
        exit
    fi
    # If user ran the script as root:
    if [ "$EUID" -eq 0 ]
    then
        printf "makepkg cannot be run as root.\n"
        exit
    fi
}

# Install package -- main component
function install {
    git clone https://aur.archlinux.org/$1
    cd ./$1
    makepkg -cirs --noconfirm
}

# Clean up environment if cancelled at any stage during installation (also runs after installation)
function cleanup {
    printf "makepkg finished. Removing build directory...\n"
    # If the working directory is equal to the current argument (i.e. they are in the package's folder)
    if [ `basename $(pwd)` = $1 ]
    then
        cd ../
        rm -rdf ./$1
    # If the working directory is not the package's folder (i.e. script is manually aborted before install function is run) 
    else [ -d ./$1 ]
        rm -rdf ./$1
    fi
}

# Shoehorn a newline in between the probable output character of SIGINT and the following contents
function interrupt {
    printf "\n"
    cleanup $1
}

# Trap SIGINT so that the script can clean up before exiting
trap "interrupt $1" INT

# Check if first argument is empty (essentially the same as "if [ $# -eq 0 ]")
if [ -z $1 ]
then
    printf "Package parameter cannot be empty.\n"
    help
fi

# Check if any of the arguments are equal to "--help"
for var in "$@"
do
    if [ $var = "--help" ]
    then
        help
    fi
done

# Iterate script on a per-argument basis for multiple packages
for var in "$@"
do
    check $var
    install $var
    cleanup $var
done

# This is a quick & dirty adaptation of a bash function I wrote for my personal use. Please inform me of anything that's not ideal.