task4_1.sh

#!/bin/bash

# Install dmidecode if not present (required for hardware fields)
if ! command -v dmidecode &>/dev/null; then
    apt-get update -qq
    apt-get install -y -qq dmidecode
fi

SCRIPT_DIR="$(dirname "$(readlink -f "$0")")"
OUTPUT_FILE="$SCRIPT_DIR/task4_1.out"

# Returns a DMI string value, or empty string when the value is not available
dmi_get() {
    local val
    val=$(dmidecode -s "$1" 2>/dev/null | grep -v "^#" | head -1 \
          | sed 's/^[[:space:]]*//;s/[[:space:]]*$//')
    case "$val" in
        "" | "Not Specified" | "Not Present" | "Unknown" \
           | "To Be Filled By O.E.M." | "Default string")
            echo "" ;;
        *)
            echo "$val" ;;
    esac
}

{
    # ------------------------------------------------------------------ Hardware
    echo "--- Hardware ---"

    cpu=$(grep -m1 "model name" /proc/cpuinfo \
          | cut -d: -f2 | sed 's/^[[:space:]]*//')
    echo "CPU: ${cpu:-Unknown}"

    ram=$(awk '/MemTotal/ { printf "%d MB", $2/1024 }' /proc/meminfo)
    echo "RAM: ${ram:-Unknown}"

    mb_mfr=$(dmi_get baseboard-manufacturer)
    mb_prod=$(dmi_get baseboard-product-name)
    [ -z "$mb_prod" ] && mb_prod="Unknown"
    if [ -n "$mb_mfr" ]; then
        echo "Motherboard: $mb_mfr $mb_prod"
    else
        echo "Motherboard: $mb_prod"
    fi

    serial=$(dmi_get system-serial-number)
    echo "System Serial Number: ${serial:-Unknown}"

    # ------------------------------------------------------------------- System
    echo "--- System ---"

    os=$(lsb_release -d --short 2>/dev/null \
         || awk -F'"' '/PRETTY_NAME/ {print $2}' /etc/os-release 2>/dev/null \
         || echo "Unknown")
    echo "OS Distribution: $os"

    echo "Kernel version: $(uname -r)"

    # Use tune2fs on the root device; fall back to /lost+found ctime
    root_dev=$(df / | awk 'NR==2 {print $1}')
    inst_date=$(tune2fs -l "$root_dev" 2>/dev/null \
                | grep "Filesystem created:" \
                | sed 's/.*Filesystem created:[[:space:]]*//')
    if [ -z "$inst_date" ]; then
        inst_date=$(stat -c %z /lost+found 2>/dev/null \
                    | awk '{print $1, $2}' \
                    | xargs -I{} date -d "{}" "+%a %b %d %T UTC %Y" 2>/dev/null \
                    || echo "Unknown")
    fi
    echo "Installation date: $inst_date"

    echo "Hostname: $(hostname)"

    # Build uptime string using only allowed words: weeks days hours minutes
    total_secs=$(awk '{print int($1)}' /proc/uptime)
    total_mins=$((total_secs / 60))
    up_w=$((total_mins / 10080))
    up_d=$(( (total_mins % 10080) / 1440 ))
    up_h=$(( (total_mins % 1440) / 60 ))
    up_m=$((total_mins % 60))
    up_parts=()
    [ "$up_w" -gt 0 ] && up_parts+=("$up_w weeks")
    [ "$up_d" -gt 0 ] && up_parts+=("$up_d days")
    [ "$up_h" -gt 0 ] && up_parts+=("$up_h hours")
    [ "$up_m" -gt 0 ] && up_parts+=("$up_m minutes")
    [ "${#up_parts[@]}" -eq 0 ] && up_parts=("0 minutes")
    up_str=""
    for part in "${up_parts[@]}"; do
        up_str="${up_str:+$up_str, }$part"
    done
    echo "Uptime: $up_str"

    echo "Processes running: $(ps --no-headers -e | wc -l)"

    echo "Users logged in: $(who | wc -l)"

    # ------------------------------------------------------------------ Network
    echo "--- Network ---"

    # List all interfaces (including loopback, VLANs, TAP, etc.)
    ip link show \
    | awk '/^[0-9]+:/ { gsub(/:$/, "", $2); gsub(/@.*/, "", $2); print $2 }' \
    | while IFS= read -r iface; do
        ips=$(ip -o -4 addr show dev "$iface" 2>/dev/null \
              | awk '{print $4}' | paste -sd ', ')
        echo "$iface: ${ips:--}"
    done

} > "$OUTPUT_FILE"