$re = '/^(.*?\/)(?=[^\/]+=).*$/m';
$str = 'my-file-path/wefw/wefw/wef/wfweof=wefonwe/wfewoi=weoif/
my-file-path/wefw/wef/ef=wefonwe/wfewoi=weoif/
my-file-path/wef/wfe/wefw/wef/ef=wefonwe/wfewoi=weoif/
Output:
file_paths
my-file-path/wefw/wefw/wef/
my-file-path/wefw/wef/
my-file-path/wef/wfe/wefw/wef/
';
$subst = "$1";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php