Check Updates List for Archlinux using checkupdates

checkupdateslist

#!/bin/env bash

# Check Updates List
#   Report and notify only when specific packages needs an update on Archlinux.
#
# Usage:
#   checkupdateslist [package]...
#
# Example:
#   $ checkupdateslist
#   $ checkupdateslist yt-dlp retroarch
#   $ checkupdateslist "*pipewire*"
#
# Required programs:
#   checkupdates notify-send grep awk wc tr
#
# On Arch:
# - checkupdates from package extra/pacman-contrib
# - notify-send from package extra/libnotify

# An optional configuration file in form of `key=value` format.
# Note that value should NOT be enclosed by quotes, as the config
# file is not a script. Supported options are basically the below
# variables.
#
# Example:
#   packages = linux firefox
#   expire_ms = 15000
#
config_file="${HOME}/.config/checkupdateslist.cfg"

# Default list of packages to check. The package names should match exactly.
# Multiple packages are separated by space. Any given arguments to the script
# will overwrite the default.
packages='linux linux-lts linux-zen'

# Time in millesconds until notify message disappears.
#   "" = (empty) do not display notification
#   0 = does not disappear automatically
#   15000 = 15 seconds
# expire_ms=""
expire_ms="0"

# Parse and load configuration file from key=value pairs.
# Whitespace surrounding key name and its value are removed.
if [ -f "${config_file}" ]; then
	while IFS='=' read -r key value; do
		key="$(echo "${key}" | awk '{$1=$1};1')"
		case "${key}" in
		"packages" | "expire_ms")
			value="$(echo "${value}" | awk '{$1=$1};1')"
			declare "${key}=${value}"
			;;
		*) ;;
		esac
	done <"${config_file}"
fi

if [[ "${#}" -gt 0 ]]; then
	packages="${*}"
fi

if [[ "${packages}" =~ [^a-zA-Z0-9*\ \-] ]]; then
	echo 'Only a-z, A-Z, 0-9, space, dash and star as a wildcard characters' \
		'allowed for list of package names.'
	exit 3
fi

if [[ "${expire_ms}" =~ [^0-9] ]]; then
	echo 'Only digits are allowed for expiration time.'
	exit 3
fi

# Prepare list as an extended regex for grep.
packages="${packages// /|}"
packages="${packages//\*/.*}"

# To test output, replace below `checkupdates` with `yay -Q` temporarily.
updateslist="$(checkupdates |
	awk '{print $1}' |
	grep -E "^(${packages})$")"

count="$(echo -n "${updateslist}" | wc -w)"

if [[ "${count}" -gt 0 ]]; then
	if [ "${expire_ms}" != "" ]; then
		title="${0##*/}"
		notify-send -a "${title}" \
			-t "${expire_ms}" \
			"${count} important update(s) available:" "${updateslist}" || exit 5
	fi
	echo "${updateslist}"
fi

exit 0

checkupdateslist.cfg

packages = linux firefox
expire_ms = 0