I found that writing a pastebin command line client can be a good exercise for both practicing and learning a new programming language. Let me tell you why.
First, a list of features that it should have:
- pasting a file that is passed as an argument
- pasting input that's piped into stdin
- support for user credentials
- persistent user credentials in a config file
- support for anonymous posting
- the ability to specify a language (for syntax highlighting)
- error handling (nothing too advanced)
- saving the new paste URL in the user's clipboard
The good thing about implementing all the above mentioned features is that you end up dealing with many essential aspects that one usually encounters when solving real tasks. These include:
- stdin handling
- file operations
- JSON/INI parsing (config file, response from pastebin server)
- HTTP requests
- creating a process and passing it input (for clipboard handling)
- command line arguments handling
- string / file path manipulation
- exceptions (invalid config file, bad HTTP request)
- understanding and using an external API
This is a nice exercise because it will not take too many lines of code (under 200, probably) and it will not eat up too much of your time either. If you want to try it out, I recommend the Refheap pastebin server because of their nice API and support for multiple languages - it even supports Rust!
An extra challenge in case you opt for the Refheap API - they have a feature that allows you to specify a file extension for the language attribute and they will infer the correct syntax highlighting settings for you.