How to use the command 'psysh' (with examples)

PsySH is a runtime developer console, interactive debugger, and read-eval-print loop (REPL) for PHP. It provides a handy interactive shell for PHP developers to experiment with code snippets in real-time, debug code, and explore existing codebases. With PsySH, developers can leverage PHP’s dynamic capabilities to inspect objects, execute code fragments, and understand complex logic in a controlled environment. Widely recognized for its flexibility and ease of use, PsySH enhances productivity by streamlining the coding and debugging process.

Open a shell in the current directory (Use case 1)

Code:

psysh

Motivation:

As a PHP developer, there are times when you need to quickly evaluate some code or test a snippet without leaving the command line. This is especially useful in projects where iterating and tweaking code are frequent. Using PsySH in the current directory means you need quick access to the project’s context—whether it’s exploring existing classes, functions, or simply checking configurations. This command opens up an interactive PHP shell directly in the command line, creating a seamless experience that mirrors your project environment closely.

Explanation:

• psysh: This command is used to invoke PsySH, which launches an interactive PHP shell. Running this command without additional arguments starts the shell in the directory from which it was called. It implies that the user’s current shell session becomes a playground where PHP code can be directly written and executed, making it highly efficient for quick tests and debugging.

Example output:

Upon running this command, the shell will display a version banner and a REPL prompt, such as:

Psy Shell v0.10.8 (PHP 7.4.3 — cli) by Justin Hileman
>>> 

Indicating that you are ready to start typing and executing PHP code.

Open a shell in a specific directory (Use case 2)

Code:

psysh --cwd path/to/directory

Motivation:

Sometimes, developers work on multiple projects simultaneously, each with distinct environments and dependencies. By opening a PsySH shell in a specific directory, you can ensure that the context of the shell session matches the specific project you are focusing on. This approach allows you to explore or debug code with the correct set of dependencies loaded, reflected by the project directory structure, effectively keeping your development work organized and context-aware.

Explanation:

• psysh: This command remains the same, invoking the PsySH tool.
• --cwd path/to/directory: The --cwd option stands for “current working directory” and tells PsySH to change the working directory to the specified path. This ensures that the shell environment and file inclusions reflect that of the given directory.

Example output:

Running the command will set the PsySH context to the specified directory and show a prompt similar to:

Changed current directory to: /full/path/to/directory
Psy Shell v0.10.8 (PHP 7.4.3 — cli) by Justin Hileman
>>> 

This confirms that your shell session is rooting from the designated directory.

Use a specific configuration file (Use case 3)

Code:

psysh --config path/to/file

Motivation:

Different projects may have unique development configurations that dictate how scripts run or how certain features behave. Upon encountering diverse environments or custom settings, altering PsySH’s default behavior becomes crucial. By using a specific configuration file, developers can ensure that the shell session adheres to custom setup preferences specific to the project in focus, such as preloaded scripts, customized shell appearance, or context-specific PHP settings.

Explanation:

• psysh: The base command invoking the PsySH session launcher.
• --config path/to/file: The --config option specifies that PsySH should use the provided configuration file instead of any available defaults. This allows developers to customize their shell environment extensively based on the content of this configuration file.

Example output:

Executing the command will load PsySH with settings from the specified configuration file, showing output like:

Using configuration file: /full/path/to/file
Psy Shell v0.10.8 (PHP 7.4.3 — cli) by Justin Hileman
>>> 

This output verifies that the specified config file is in effect for the session.

Conclusion:

PsySH is a powerful and versatile tool for PHP developers, streamlining the process of testing and debugging PHP code in real-time. Whether you’re executing the shell in the current directory for quick tests, tailoring a session to work from a specific project directory, or employing a custom configuration for enhanced control, PsySH significantly enhances productivity and developer workflow. When mastered, this tool can become an essential asset in any PHP developer’s toolbox, offering flexibility and immediate feedback unmatched by standard debugging solutions.