As a software developer, I’ve had my fair share of moments when my app works perfectly on my trusty Windows machine… until I deploy it on a Linux server and it crashes spectacularly. That frustrating gap between “It runs fine here” and “Why won’t it run there?” recently hit me hard during a .NET Core project. I want to share my experience because, believe me, you’re not alone in this!

The Problem

I had just finished building a neat little app that worked flawlessly on my local Windows setup. Excited, I pushed it to a Linux-based server and… boom. It crashed. No helpful error message, just silence. After some head-scratching and caffeine-fueled debugging, I realized the culprit: differences between Windows and Linux environments, specifically case-sensitive file paths, line endings, and path separators.

Windows is forgiving: file paths like Config.json and config.json often point to the same file. Linux? Not so much. It treats them as completely different files. Plus, Windows uses backslashes \ in paths, while Linux uses forward slashes /. These subtle differences can cause your .NET Core app to break when crossing platform boundaries.

The Solution

Once I spotted the problem, the fix wasn’t too complicated but took some digging. I updated my code to use Path.Combine() from the .NET Core library, which handles path separators automatically. I also made sure to check file names carefully for case sensitivity — no more accidental mismatches! And for line endings, I converted text files to use Linux-style endings (\n) when deploying.

It’s worth noting that the case-sensitivity behaviour is actually part of the .NET runtime itself. According to Microsoft’s official documentation:

The case-sensitivity of the path parameter corresponds to that of the file system on which the code is running. For example, it’s case-insensitive on NTFS (the default Windows file system) and case-sensitive on Linux file systems.

This perfectly explains why my app worked on Windows but crashed on Linux. (Source: Microsoft Docs)

A Deeper Explanation

Why does this happen? Windows and Linux have different file system conventions due to their history and design. Windows’ case-insensitivity means it treats “File.txt” and “file.txt” as the same file, whereas Linux’s case-sensitivity treats them as two distinct files. This can be a headache when your code hardcodes file names or relies on user input.

Similarly, file paths in Windows are written like C:\Projects\MyApp, but Linux expects /home/user/MyApp. Luckily, Path.Combine() and related .NET APIs abstract these differences, making your life easier if you use them consistently.

Best Practices

• Always use platform-agnostic APIs like Path.Combine() instead of manually building paths.
• Double-check file names for case sensitivity, especially if you’re reading or writing files.
• Be mindful of line endings if you’re dealing with text files—tools like Git can help manage this with .gitattributes.
• Test your app in the target environment early and often to catch these issues before deployment.

Conclusion

Cross-platform development isn’t just about writing code that works; it’s about understanding the quirks of each platform. My Linux crash was frustrating, but it pushed me to write cleaner, more robust code. If your app worked locally — but crashed on Linux — take heart! With some patience and attention to detail, you can squash these bugs and make your code truly cross-platform. Keep coding, keep learning!