[SOLVED] Regex in bash: extract string with single or double quotes

Issue

I would like to extract database access information from a wordpress wp-config.php file.

Example (double quotes):

define( "DB_NAME", "mydatabase" );

But it might as well look like this (single quotes)

define( 'DB_NAME', 'mydatabase' );

A mixed version is also possible:

define( 'DB_NAME', "mydatabase" );

So far I have found this on the internet:

DBNAME=`cat wp-config.php | grep DB_NAME | cut -d \' -f 4`

This works when single quotes are used. What I am looking for is a regex that would handle all cases.

Thank you

Solution

Input file

$ cat wp-config.php
define( 'DB_NAME', "mydatabase" );

or

$ cat wp-config.php
define( 'DB_NAME', 'mydatabase" );

With php:

php -r 'require_once("wp-config.php"); echo DB_NAME;'

With GNU grep:

$ grep -oP "^define.*?DB_NAME.*?[\042\047]\K[\w.]+" wp-config.php

Output

mydatabase

Answered By - Gilles Quénot

Answer Checked By - Robin (WPSolving Admin)