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Display debug message prefixed with "Debug: " when --debug is used.

WP_CLI::debug( $message, $group = false )

Debug message is written to STDERR, and includes script execution time.

Helpful for optionally showing greater detail when needed. Used throughout WP-CLI bootstrap process for easier debugging and profiling.

# Called in `WP_CLI\Runner::set_wp_root()`.
private static function set_wp_root( $path ) {
    define( 'ABSPATH', rtrim( $path, '/' ) . '/' );
    WP_CLI::debug( 'ABSPATH defined: ' . ABSPATH );
    $_SERVER['DOCUMENT_ROOT'] = realpath( $path );
}

# Debug details only appear when `--debug` is used.
# $ wp --debug
# [...]
# Debug: ABSPATH defined: /srv/www/wordpress-develop.dev/src/ (0.225s)

Internal API documentation is generated from the WP-CLI codebase on every release. To suggest improvements, please submit a pull request.

• WP_CLI\Utils\format_items() - Render a collection of items as an ASCII table, JSON, CSV, YAML, list of ids, or count.
• WP_CLI\Utils\make_progress_bar() - Create a progress bar to display percent completion of a given operation.
• WP_CLI::colorize() - Colorize a string for output.
• WP_CLI::line() - Display informational message without prefix, and ignore `--quiet`.
• WP_CLI::log() - Display informational message without prefix.
• WP_CLI::success() - Display success message prefixed with "Success: ".
• WP_CLI::warning() - Display warning message prefixed with "Warning: ".
• WP_CLI::error() - Display error message prefixed with "Error: " and exit script.
• WP_CLI::error_multi_line() - Display a multi-line error message in a red box. Doesn't exit script.