Bash Projects

#!/usr/bin/env bash
set -euo pipefail

check_disk() {
    local usage
    usage=$(df / | awk 'NR==2 {print $5}' | tr -d '%')
    [ "$usage" -lt 90 ] && echo "OK: Disk usage ${usage}%" || { echo "CRITICAL: Disk usage ${usage}%" >&2; return 1; }
}

check_memory() {
    local available
    available=$(free | awk '/Mem/ {printf "%.0f", $7/$2 * 100}')
    [ "$available" -gt 10 ] && echo "OK: ${available}% memory available" || { echo "CRITICAL: only ${available}% memory available" >&2; return 1; }
}

check_load() {
    local load cores
    load=$(uptime | awk -F'load average:' '{print $2}' | awk -F, '{print $1}' | tr -d ' ')
    cores=$(nproc)
    echo "Load: $load (cores: $cores)"
}

main() {
    local failed=0
    check_disk || failed=1
    check_memory || failed=1
    check_load
    exit "$failed"
}
main "$@"

#!/usr/bin/env bash
set -euo pipefail

LOGFILE="${1:?Usage: $0 <logfile> [threshold]}"
THRESHOLD="${2:-50}"

ERROR_COUNT=$(grep -c "ERROR" "$LOGFILE" || true)
echo "Errors found: $ERROR_COUNT (threshold: $THRESHOLD)"

if [ "$ERROR_COUNT" -gt "$THRESHOLD" ]; then
    echo "=== Top error types ==="
    grep "ERROR" "$LOGFILE" | awk -F'ERROR: ' '{print $2}' | sort | uniq -c | sort -rn | head -5
    [ -n "${WEBHOOK_URL:-}" ] && curl -sf -X POST -H 'Content-Type: application/json' \
        -d "{\"text\":\"Alert: $ERROR_COUNT errors in $LOGFILE\"}" "$WEBHOOK_URL"
    exit 1
fi

#!/usr/bin/env bash
set -euo pipefail

SOURCE_DIR="${1:?Usage: $0 <source_dir> <dest_dir>}"
DEST_DIR="${2:?Usage: $0 <source_dir> <dest_dir>}"
DATE=$(date +%Y%m%d-%H%M%S)
ARCHIVE="$DEST_DIR/backup-$DATE.tar.gz"
RETENTION_DAYS=30

mkdir -p "$DEST_DIR"
tar -czf "$ARCHIVE" -C "$(dirname "$SOURCE_DIR")" "$(basename "$SOURCE_DIR")"
echo "Backup created: $ARCHIVE ($(du -h "$ARCHIVE" | cut -f1))"

find "$DEST_DIR" -name "backup-*.tar.gz" -mtime "+$RETENTION_DAYS" -print -delete
echo "Cleaned up backups older than $RETENTION_DAYS days"

0 2 * * * /usr/bin/bash /opt/scripts/backup.sh /data /backups >> /var/log/backup.log 2>&1

#!/usr/bin/env bash
set -euo pipefail

SERVERS=("web1.example.com" "web2.example.com" "web3.example.com")
APP_DIR="/opt/myapp"
FAILED_SERVERS=()

deploy_to_server() {
    local server="$1"
    ssh -o BatchMode=yes "deploy@$server" bash -s << EOF
        set -e
        cd "$APP_DIR"
        git pull origin main
        systemctl restart myapp
        sleep 3
        systemctl is-active --quiet myapp
EOF
}

for server in "${SERVERS[@]}"; do
    echo "Deploying to $server..."
    if deploy_to_server "$server"; then
        echo "$server: OK"
    else
        echo "$server: FAILED" >&2
        FAILED_SERVERS+=("$server")
    fi
done

if [ "${#FAILED_SERVERS[@]}" -gt 0 ]; then
    echo "Deployment failed on: ${FAILED_SERVERS[*]}" >&2
    exit 1
fi
echo "Deployed successfully to all ${#SERVERS[@]} servers"

#!/usr/bin/env bash
set -euo pipefail

REGION="${1:-us-east-1}"

echo "=== Unattached EBS Volumes (potential cost savings) ==="
aws ec2 describe-volumes --region "$REGION" --filters "Name=status,Values=available" \
    --query 'Volumes[*].[VolumeId,Size,CreateTime]' --output table

echo "=== Untagged Running Instances ==="
aws ec2 describe-instances --region "$REGION" \
    --filters "Name=instance-state-name,Values=running" \
    --query "Reservations[].Instances[?!not_null(Tags[?Key=='Environment'])].[InstanceId,InstanceType]" \
    --output table

echo "=== S3 Buckets Without Versioning Enabled ==="
for bucket in $(aws s3api list-buckets --query 'Buckets[*].Name' --output text); do
    STATUS=$(aws s3api get-bucket-versioning --bucket "$bucket" --query 'Status' --output text 2>/dev/null || echo "None")
    [ "$STATUS" != "Enabled" ] && echo "$bucket: $STATUS"
done