Creating a bash script to install packages

Question

I'm quite a newbie when it comes to bash. I'm trying to create a script that checks whether a package is installed or not. If not it will install that package. Not sure what I'm doing tbh.

#! /bin/bash
echo Installing/Checking packages from list

declare -a PKGS=("libreoffice", "firefox", "virtualbox", "vlc")
    
PKG_OK=$(dpkg-i -W --showformat='${Status}\n' PKGS |grep "install ok installed")


for i in "${PKGS[@]}"
do
    if [ "" = "$PKG_OK" ]; then
        echo "No $PKGS, installing the package now"
        sudo apt install $PKGS[@]
    fi
done

Answer 1

Simply:

#!/bin/bash

pkgs=(libreoffice firefox virtualbox vlc)
sudo apt-get -y --ignore-missing install "${pkgs[@]}" 

• the packages already installed will be ignored automatically
• those that are not accessible will be ignored too with --ignore-missing
• prefer apt-get than apt for scripting

From man apt:

apt provides a high-level commandline interface for the package management system. It is intended as an end user interface and enables some options better suited for interactive usage by default compared to more specialized APT tools like apt-get(8)

---

Another approach that I use personally, is to add every needed packages in a file line by line:

packages.list:

moreutils
util-linux
strace

Then I can call:

apt-get -y --ignore-missing install $(< packages.list)

Answer 2

I am also a noob to shell scripting, honestly i don't know about your approach but this is what I would do instead.

#!/usr/bin/env bash

declare -a PKGS=(libreoffice firefox virtualbox vlc)
for i in "${PKGS[@]}"; do
    check=$(command -v "$i")
    if [[ $? -ne 0 ]]; then
        sudo apt install "$i"
    fi
done