Resolving the eval: syntax error near unexpected token 'then' in BASH Scripts

Discover effective solutions for the `eval: syntax error near unexpected token 'then'` error in BASH scripts. Simplify your scripting process and avoid frustrating pitfalls! --- This video is based on the question https://stackoverflow.com/q/66361400/ asked by the user 'Steve Coulter' ( https://stackoverflow.com/u/9954262/ ) and on the answer https://stackoverflow.com/a/66361836/ provided by the user 'Jerry Jeremiah' ( https://stackoverflow.com/u/2193968/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions. Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Why am i getting error "eval: syntax error near unexpected token `then'"? BASH Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/licensing The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/by-sa/4.0/ ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/by-sa/4.0/ ) license. If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com. --- Resolving the eval: syntax error near unexpected token 'then' in BASH Scripts If you are working with BASH scripts, you may have encountered the error message: eval: syntax error near unexpected token 'then'. This error can be quite confusing, especially if you're not sure what caused it. In this guide, we will unravel the complexities of this issue and provide you with an effective solution. Let's dive in! Understanding the Problem The error occurs when you attempt to run a series of commands using the eval command in BASH. The exact line triggering the error may look something like this: [[See Video to Reveal this Text or Code Snippet]] Here's what happens during execution: The STARTUP variable is defined to check if a file (entrypoint.sh) exists and, if so, execute a command ({{COMMAND}}). The eval command is intended to evaluate the generated script from the STARTUP variable. Due to syntax misalignments, particularly around the use of then, the script encounters errors when interpreted by the shell. This leads to the dreaded syntax error near unexpected token 'then'. Let's break down how to fix this. Breaking Down the Solution 1. Diagnosing the Error The critical issue arises from how the commands are structured. When the command substitution ($(...)) takes place, it evaluates the command and can create unexpected results. This often results in a valid then without a preceding if, leading to the syntax error. 2. Altering the Quoting One way to correct the issue is to alter how we handle quoting within the EVAL_SCRIPT. By modifying the quotes carefully, we can ensure that the script evaluates as intended. Here's the correction you need: [[See Video to Reveal this Text or Code Snippet]] This approach ensures that the complete script is passed correctly to eval, retaining the necessary structure to avoid syntax issues. 3. Executing the Corrected Script After obtaining a correctly formatted string for EVAL_SCRIPT, you need to ensure you execute it using eval correctly. Instead of running the command as-is: [[See Video to Reveal this Text or Code Snippet]] You should use: [[See Video to Reveal this Text or Code Snippet]] By using eval, you allow BASH to properly interpret and execute the constructed command. 4. Simplifying the Code Finally, you can simplify your code by removing unnecessary subshells and evals. The original script can be reduced without losing functionality. Here's a more streamlined version: [[See Video to Reveal this Text or Code Snippet]] Conclusion Dealing with errors in BASH scripting can often feel daunting, but by understanding the nuances of commands like eval, you can navigate through these pitfalls. In this post, we've explained the eval: syntax error near unexpected token 'then' issue, provided a breakdown of the fix, and simplified the script for better practice. By following these guidelines, you will be able to write cleaner, more efficient BASH scripts while avoiding common errors.