Website Uptime Monitoring Script in Bash

Why use curl for website uptime checks?

ping can tell you whether a host responds to ICMP, but it does not tell you whether a website is returning 200 OK, redirecting, timing out or throwing a 500 error. curl is better for website uptime checks because it talks HTTP and HTTPS.

Check one website URL

Create a script called check-url-uptime.sh.

#!/usr/bin/env bash

URL="${1:-}"
TIMEOUT="${2:-10}"

if [ -z "$URL" ]; then
  echo "Usage: $0 url [timeout-seconds]"
  exit 1
fi

result="$(curl -L -sS -o /dev/null \
  --max-time "$TIMEOUT" \
  -w '%{http_code} %{time_total} %{remote_ip}' \
  "$URL" 2>/dev/null)" || {
    echo "[CRITICAL] $URL failed to respond within ${TIMEOUT}s"
    exit 2
  }

status="$(awk '{print $1}' <<< "$result")"
time_total="$(awk '{print $2}' <<< "$result")"
remote_ip="$(awk '{print $3}' <<< "$result")"

if [[ "$status" =~ ^2|3 ]]; then
  echo "[OK] $URL status=$status time=${time_total}s ip=$remote_ip"
  exit 0
else
  echo "[WARN] $URL status=$status time=${time_total}s ip=$remote_ip"
  exit 1
fi

Run it:

chmod +x check-url-uptime.sh
./check-url-uptime.sh https://example.com

[OK] https://example.com status=200 time=0.184s ip=93.184.216.34

[WARN] https://example.com/missing-page status=404 time=0.152s ip=93.184.216.34

How the curl command works

curl -L -sS -o /dev/null --max-time 10 -w '%{http_code} %{time_total}\n' https://example.com

200 0.184321

Check multiple websites from a file

Create a file named urls.txt.

https://example.com
https://commandlinequiz.com
# Add one URL per line

Create check-websites-list.sh:

#!/usr/bin/env bash

URL_FILE="${1:-urls.txt}"
TIMEOUT="${2:-10}"
LOG_FILE="${3:-./uptime-monitor.log}"

if [ ! -f "$URL_FILE" ]; then
  echo "URL file not found: $URL_FILE"
  exit 1
fi

check_url() {
  local url="$1"
  local result status time_total remote_ip timestamp

  timestamp="$(date -Is)"

  result="$(curl -L -sS -o /dev/null \
    --max-time "$TIMEOUT" \
    -w '%{http_code} %{time_total} %{remote_ip}' \
    "$url" 2>/dev/null)" || {
      echo "[$timestamp] [CRITICAL] $url failed timeout=${TIMEOUT}s" | tee -a "$LOG_FILE"
      return 2
    }

  status="$(awk '{print $1}' <<< "$result")"
  time_total="$(awk '{print $2}' <<< "$result")"
  remote_ip="$(awk '{print $3}' <<< "$result")"

  if [[ "$status" =~ ^2|3 ]]; then
    echo "[$timestamp] [OK] $url status=$status time=${time_total}s ip=$remote_ip" | tee -a "$LOG_FILE"
    return 0
  else
    echo "[$timestamp] [WARN] $url status=$status time=${time_total}s ip=$remote_ip" | tee -a "$LOG_FILE"
    return 1
  fi
}

overall=0

while IFS= read -r url; do
  [[ -z "$url" || "$url" =~ ^# ]] && continue
  check_url "$url" || overall=1
done < "$URL_FILE"

exit "$overall"

[2026-05-03T15:04:11+01:00] [OK] https://example.com status=200 time=0.184s ip=93.184.216.34
[2026-05-03T15:04:12+01:00] [OK] https://commandlinequiz.com status=200 time=0.221s ip=104.21.10.123

Log uptime results

The multiple URL script writes to uptime-monitor.log by default.

tail -f uptime-monitor.log

[2026-05-03T15:04:11+01:00] [OK] https://example.com status=200 time=0.184s ip=93.184.216.34
[2026-05-03T15:04:12+01:00] [OK] https://commandlinequiz.com status=200 time=0.221s ip=104.21.10.123
[2026-05-03T15:09:11+01:00] [WARN] https://example.org status=500 time=0.293s ip=93.184.216.34

You can pass a custom log path as the third argument:

./check-websites-list.sh urls.txt 10 /var/log/uptime-monitor.log

Run the uptime monitor from cron

To run every 5 minutes, add a cron entry:

crontab -e

*/5 * * * * /home/exampleuser/check-websites-list.sh /home/exampleuser/urls.txt 10 /home/exampleuser/uptime-monitor.log >/dev/null 2>&1

Run the monitor with systemd

For a cleaner server setup, create a service and timer. This integrates with journalctl.

# /etc/systemd/system/website-uptime.service
[Unit]
Description=Check website uptime

[Service]
Type=oneshot
ExecStart=/usr/local/bin/check-websites-list.sh /etc/website-urls.txt 10 /var/log/website-uptime.log

# /etc/systemd/system/website-uptime.timer
[Unit]
Description=Run website uptime check every 5 minutes

[Timer]
OnBootSec=2min
OnUnitActiveSec=5min
Unit=website-uptime.service

[Install]
WantedBy=timers.target

sudo systemctl daemon-reload
sudo systemctl enable --now website-uptime.timer
systemctl list-timers website-uptime.timer

For more detail, see the systemd guide.

Download the example scripts

What to check when a website fails

Useful related guides: Basic Networking Commands, firewalld Guide, Search Logs for Errors.

Common uptime monitor mistakes

• Using ping as proof that a website works. A server can ping but still return HTTP 500.
• Not using a timeout, causing scripts to hang.
• Ignoring redirects when the expected URL redirects to HTTPS.
• Only checking one page when the homepage is cached but the application is broken.
• Running from cron with relative paths that do not resolve correctly.
• Not logging failures, which turns monitoring into “I swear it was broken earlier”.