Do An Action Only After One Is Completed Bash

Shell Programming

Throughout my experience as a developer, I’ve often encountered the need to perform a specific action only after another one has been successfully completed in a bash script. This can be a crucial requirement, especially when working on automation tasks or complex system operations. In this article, I’ll share some insights into how I have tackled this challenge and provide a detailed guide on how you can achieve this in your own bash scripts.

The Importance of Sequencing Actions in Bash

As I’ve delved into the world of bash scripting, I’ve come to appreciate the significance of executing tasks in a specific order. There are scenarios where one task must be finished before another can begin, such as when handling file operations, database queries, or network operations. Without proper sequencing, the integrity and success of the entire script can be compromised.

Using Conditional Statements

One method that I rely on to ensure that an action is only performed after another is completed is by utilizing conditional statements. Within bash scripting, the if-else construct plays a vital role in executing commands based on specific conditions. By incorporating this into the script, I can check for the successful completion of the preceding action before allowing the subsequent one to proceed.

Implementing Functions

Another approach that I find useful is the utilization of functions to encapsulate certain actions. By carefully structuring the functions within the script, I can control the order in which they are called. This enables me to enforce a sequential flow, ensuring that each function executes only after its preceding function has finished its task.

Using Exit Codes

One of the most reliable methods for determining the success or failure of a command in bash is by examining its exit code. By capturing the exit code of a command or action, I can make informed decisions on whether to proceed with the next action or to handle potential errors gracefully.

Practical Example

Let’s consider a scenario where a file needs to be compressed only after it has been successfully created. In my own projects, I’ve employed a combination of conditional statements and exit code validation to achieve this. By checking the exit code of the file creation command, I can then proceed to initiate the compression process if the creation was successful.


        # Example Bash Script
        create_file_command
        if [ $? -eq 0 ]; then
            compress_file_command
        fi
    

Conclusion

As I’ve navigated the intricacies of bash scripting, I’ve realized the immense value of ensuring a sequential flow of actions within scripts. By leveraging conditional statements, functions, and exit codes, I’ve been able to orchestrate the precise execution of tasks, leading to more robust and reliable scripts. I encourage you to explore these techniques in your own scripting endeavors, and I’m confident that you’ll find them invaluable in achieving your automation and system operation goals.