10 Bash scripts that every beginner DevOps engineer can use to automate workflows

1. Update and Upgrade System Packages

Scenario: Your server needs to be updated with the latest security patches.
Script:

#!/bin/bash
echo "Updating system packages..."
sudo apt update && sudo apt upgrade -y
echo "System updated successfully!"

What it does: Ensures your server is updated.

Steps:

• sudo apt update: Checks for new updates.

• sudo apt upgrade -y: Installs updates automatically.

2. Monitor Disk Space

Scenario: You want to avoid your server running out of storage space.
Script:

#!/bin/bash
THRESHOLD=80
echo "Checking disk usage..."
USAGE=$(df / | tail -1 | awk '{print $5}' | sed 's/%//')
if [ "$USAGE" -gt "$THRESHOLD" ]; then
  echo "Warning! Disk usage is above $THRESHOLD%. Current usage: $USAGE%"
else
  echo "Disk usage is fine. Current usage: $USAGE%"
fi

What it does: Alerts you if the disk usage exceeds 80%.

3. Automate File Backups

Scenario: You need daily backups for a critical directory.
Script:

#!/bin/bash
SOURCE="/path/to/source"
DEST="/path/to/backup"
DATE=$(date +%Y-%m-%d)
echo "Backing up files from $SOURCE to $DEST/$DATE..."
mkdir -p "$DEST/$DATE"
cp -r "$SOURCE"/* "$DEST/$DATE"
echo "Backup completed!"

What it does: Creates a backup folder with the current date and copies files into it.

4. Deploy a Simple Web Server

Scenario: Quickly set up a basic web server for testing.
Script:

#!/bin/bash
echo "Installing Nginx..."
sudo apt update
sudo apt install -y nginx
echo "Starting Nginx service..."
sudo systemctl start nginx
sudo systemctl enable nginx
echo "Nginx web server is ready!"

What it does: Installs and starts Nginx, a lightweight web server.

5. Add and Manage Users

Scenario: You need to create a new user with admin rights.
Script:

#!/bin/bash
USERNAME="newuser"
PASSWORD="password123"
GROUP="sudo"
echo "Creating user $USERNAME..."
sudo useradd -m -s /bin/bash "$USERNAME"
echo "$USERNAME:$PASSWORD" | sudo chpasswd
echo "Adding $USERNAME to $GROUP group..."
sudo usermod -aG "$GROUP" "$USERNAME"
echo "User $USERNAME created with admin privileges!"

What it does: Creates a user, sets a password, and grants admin access.

6. Check Server Uptime

Scenario: You want to know how long your server has been running without restarting.
Script:

#!/bin/bash
echo "Server uptime:"
uptime

What it does: Displays the server’s uptime and system load.

7. Check Active Processes

Scenario: Your server is slow, and you want to find resource-heavy processes.
Script:

#!/bin/bash
echo "Top 5 processes by CPU usage:"
ps -eo pid,ppid,cmd,%mem,%cpu --sort=-%cpu | head -6

What it does: Lists the top 5 processes using the most CPU.

8. Automate SSH Key Generation

Scenario: You need a secure key for connecting to another server without a password.
Script:

#!/bin/bash
KEY_NAME="id_rsa"
echo "Generating SSH key..."
ssh-keygen -t rsa -b 4096 -f "$HOME/.ssh/$KEY_NAME" -N ""
echo "SSH key generated at $HOME/.ssh/$KEY_NAME"

What it does: Creates an SSH key pair for secure connections.

9. Restart a Service

Scenario: Your web server stops unexpectedly, and you want to restart it automatically.
Script:

#!/bin/bash
KEY_NAME="id_rsa"
echo "Generating SSH key..."
ssh-keygen -t rsa -b 4096 -f "$HOME/.ssh/$KEY_NAME" -N ""
echo "SSH key generated at $HOME/.ssh/$KEY_NAME"

What it does: Checks if a service (e.g., Nginx) is running and restarts it if it’s not.

10. Schedule a Cron Job

Scenario: You need a script to run automatically every day at 2 AM.
Script:

#!/bin/bash
JOB="0 2 * * * /path/to/script.sh"
CRON_FILE="/tmp/mycron"
echo "Adding cron job..."
(crontab -l 2>/dev/null; echo "$JOB") | crontab -
echo "Cron job added successfully!"

What it does: Schedules a script (/path/to/script.sh) to run at 2 AM daily.

Tips for Running Scripts:

1. Save the Script: Use a .sh file, e.g., script.sh.

2. Make it Executable: Run chmod +x script.sh.

3. Run It: Use ./script.sh to execute the script.

4. Debugging: Use bash -x script.sh if you face errors.

With these scripts, you can automate many repetitive tasks, saving time and ensuring consistency in your DevOps workflow!