how to check what version of erlang i have

Natashya

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26-12-2024

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Determining your Erlang version is crucial for various reasons, from ensuring compatibility with specific libraries and applications to troubleshooting issues. Luckily, checking your Erlang version is a straightforward process. This guide will walk you through several methods, ensuring you can quickly identify your Erlang installation details.

Method 1: Using the erlang command in your terminal

This is the most common and easiest way to check your Erlang version.

1. Open your terminal or command prompt. The method for doing this varies depending on your operating system (Windows, macOS, Linux).

2. Type erl and press Enter. This will start the Erlang shell.

3. Type erlang:system_info(otp_release). and press Enter. This command retrieves the Erlang/OTP release information, which includes the version number.

4. Examine the output. The shell will display the Erlang version. For example, you might see something like:

{ok,"25"}

This indicates you are running Erlang/OTP 25. The exact output will vary depending on your version.

5. Exit the Erlang shell. Type halt(). and press Enter to close the shell.

Method 2: Checking the Erlang Installation Directory

If you can't access the Erlang shell, you can try this alternative:

1. Locate your Erlang installation directory. The location varies based on your operating system and how you installed Erlang. Common locations include:

   • Linux/macOS: /usr/local/lib/erlang/<version> or /usr/lib/erlang/<version>
   • Windows: C:\Program Files\erl<version>

2. Examine the directory name. The version number is often included as part of the directory name. For instance, a directory named erl10 indicates Erlang version 10. This method provides a less precise version than Method 1, however.

Method 3: Using the erl -version command (Some systems)

Some systems support a direct -version flag:

1. Open your terminal or command prompt.

2. Type erl -version and press Enter. This command directly outputs the Erlang version without starting the shell.

3. Check the output. Similar to Method 1, the version number will be displayed. Note that this method might not work on all systems.

Troubleshooting

If you encounter issues:

• Ensure Erlang is correctly installed. If you cannot find the Erlang directory or the erl command isn't recognized, reinstall Erlang.
• Check your PATH environment variable. This variable tells your system where to find executables. If Erlang isn't in your PATH, you won't be able to run the erl command. Consult your operating system's documentation on how to manage environment variables.
• Multiple Erlang versions: If you have multiple Erlang installations, make sure you're using the correct one. You might need to specify the path to the desired Erlang executable.

By using these methods, you can easily determine which Erlang version you have installed, allowing for smoother development and troubleshooting. Remember to always check your Erlang version before starting new projects to ensure compatibility and avoid unexpected errors.