readline_add_history() adds a line to the in-memory readline command history. This guide explains the function with focused examples and the decisions that matter in real applications.
What Is readline_add_history() in PHP?
Adds a line to the in-memory readline command history.
A typical call looks like this:
<?php
readline_add_history($prompt);
The input arguments shown in the call identify the relevant connection, resource, value, path or configuration for the operation. Pay attention to argument order and to the return value demonstrated below.
Example 1: Basic Usage
This first example uses readline_add_history() directly to demonstrate its basic purpose.
<?php
readline_add_history("list");
The returned value illustrates adds a line to the in-memory readline command history. Avoid saving passwords or secrets in history.
Example 2: A Different Input or Option
The next example changes the input or option, showing another supported use of readline_add_history().
<?php
readline_add_history("help");
The returned value illustrates adds a line to the in-memory readline command history. Avoid saving passwords or secrets in history.
Practical Example: Applying the Function
In application code, readline_add_history() belongs in a controlled workflow with input validation, a checked result and cleanup where needed.
<?php
$command = "status"; readline_add_history($command); print_r(readline_list_history());
The returned value illustrates adds a line to the in-memory readline command history. Avoid saving passwords or secrets in history.
Important Behavior and Edge Cases
- Main behavior: Adds a line to the in-memory readline command history.
- Important limitation: Avoid saving passwords or secrets in history.
- Requirements: This function uses the CLI readline extension; it is not designed for an ordinary web request.
Comparison With Related Functions
| Function or Approach | When to Use It |
|---|---|
readline_add_history() | Adds a line to the in-memory readline command history. |
readline_list_history | Returns recorded readline history entries in an array. |
Common Beginner Mistakes
| Mistake | Correct Approach |
|---|---|
Ignoring the specific limits or preconditions of readline_add_history(). | Avoid saving passwords or secrets in history. |
| Assuming every environment produces the same result. | This function uses the CLI readline extension; it is not designed for an ordinary web request. |
Key Takeaways
- Adds a line to the in-memory readline command history.
- Avoid saving passwords or secrets in history.
- This function uses the CLI readline extension; it is not designed for an ordinary web request.
Use readline_add_history() when its behavior matches your task, and verify the relevant return value before taking further action. The output depends on the local configuration when it uses resources, files or an interactive terminal.