$re = '@(?<=/)[\s\w\.-]+$@m';
$str = './Old Project
./Old Project/Manuscript.docx
./Old Project/Data Analysis
./Old Project/Data Analysis/Working Syntax.sps
./Old Project/Data Analysis/Raw data
./Old Project/Data Analysis/Working Data.sav
./Old Project/Data Analysis/Figures
./Old Project/Data Analysis/Figures/Figure 2.png
./Old Project/Data Analysis/Figures/Figure 1.png
./Old Project/Data Analysis/Raw Data
./Old Project/Data Analysis/Raw Data/2020-06-26.csv
./Old Project/Data Analysis/Cleaned Data.sav
./Old Project/Ethics
./Old Project/Ethics/Informed Consent.docx
./Old Project/Ethics/Application.pdf
./Old Project/Ethics/Approval.pdf
./Old Project/Abstract.rtf';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
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