Create linux_os_update_check.sh

scripts_staging/linux_os_update_check.sh

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+#!/bin/bash
+
+# Synopsis:
+# This script is designed to check for available package updates on Linux systems. It supports multiple package
+# managers, including apt-get (used by Debian-based distributions like Ubuntu), dnf (used by Fedora), and yum
+# (used by CentOS and RHEL). The script identifies which package manager is available on the system and uses it
+# to check for updates. If updates are available, it lists them and exits with code 1. If updates cannot be checked,
+# it exits with code 2. If there are no updates, it exits with code 0.
+
+# Exit Codes:
+# 0 - Success: No updates are available.
+# 1 - Error: Updates are available (this script treats the availability of updates as an actionable item, thus 'Error').
+# 2 - Warning: The script was unable to check for updates, possibly due to an unsupported package manager or other issue.
+
+# The script provides a straightforward way for administrators and scripts to check for software updates across a
+# variety of Linux distributions using Tactical RMM, simplifying maintenance tasks and ensuring systems can be kept up to date with
+# minimal manual intervention.
+
+#!/bin/bash
+
+# Function to check for updates using apt-get
+check_apt_get() {
+    apt-get update > /dev/null
+    UPDATES=$(apt-get -s upgrade | awk '/^Inst/ { print $2 }')
+    if [ -n "$UPDATES" ]; then
+        echo "Updates available:"
+        echo "$UPDATES"
+        exit 1
+    fi
+}
+
+# Function to check for updates using dnf
+check_dnf() {
+    UPDATES=$(dnf check-update | awk '{if (NR!=1) {print $1}}')
+    if [ -n "$UPDATES" ]; then
+        echo "Updates available:"
+        echo "$UPDATES"
+        exit 1
+    fi
+}
+
+# Function to check for updates using yum
+check_yum() {
+    UPDATES=$(yum check-update | awk '{if (NR!=1 && !/Loaded plugins/) {print $1}}')
+    if [ -n "$UPDATES" ]; then
+        echo "Updates available:"
+        echo "$UPDATES"
+        exit 1
+    fi
+}
+
+# Determine which package manager is available and check for updates
+if command -v apt-get &> /dev/null; then
+    check_apt_get
+elif command -v dnf &> /dev/null; then
+    check_dnf
+elif command -v yum &> /dev/null; then
+    check_yum
+else
+    echo "Unable to determine package manager or check updates."
+    exit 2
+fi
+
+echo "No updates available."
+exit 0