How to make a bash script executable?

Making a Bash Script Executable

In the Linux operating system, a Bash script is a text file containing a series of commands that can be executed by the Bash shell. To make a Bash script executable, you need to follow these steps:

Step 1: Create a Bash Script

First, you need to create a Bash script file. You can use a text editor like Vim, Emacs, or Nano to create the file. For example, let's create a script called my_script.sh:

#!/bin/bash

echo "Hello, World!"

The first line, #!/bin/bash, is called the shebang line. It tells the operating system which interpreter to use to execute the script.

Step 2: Make the Script Executable

By default, a Bash script is not executable. To make it executable, you need to use the chmod command to change the file's permissions. The chmod command stands for "change mode" and allows you to modify the read, write, and execute permissions of a file.

To make the my_script.sh file executable, run the following command in the terminal:

chmod +x my_script.sh

The +x option adds the execute permission to the file.

Step 3: Execute the Script

Now that the script is executable, you can run it by typing the following command in the terminal:

./my_script.sh

The . represents the current directory, and the ./ tells the shell to look for the script in the current directory.

Alternatively, you can also run the script by typing the script's name directly, assuming the current directory is in your system's PATH environment variable:

my_script.sh

This will work as long as the current directory is in your system's PATH.

Real-World Example: Automating a Backup Script

Let's consider a real-world example where you want to create a Bash script to automate a backup process. Imagine you have a directory called important_files that you want to back up regularly. You can create a Bash script to handle this task:

#!/bin/bash

# Set the source and destination directories
SRC_DIR="/home/user/important_files"
BACKUP_DIR="/home/user/backups"

# Create the backup directory if it doesn't exist
mkdir -p "$BACKUP_DIR"

# Perform the backup
tar -czf "$BACKUP_DIR/backup_$(date +%Y-%m-%d).tar.gz" "$SRC_DIR"

echo "Backup complete!"

In this example, the script creates a backup of the important_files directory and stores it in the backups directory with a filename that includes the current date.

To make this script executable, you would run the following command:

chmod +x backup_script.sh

Then, you can run the script by typing:

./backup_script.sh

This script can be scheduled to run automatically using a cron job or a task scheduler, making it a convenient way to automate your backup process.

In conclusion, making a Bash script executable is a simple process that involves creating the script, making it executable using the chmod command, and then running the script. This allows you to automate various tasks and streamline your workflow on a Linux system.