Leafpad is a text editor for the LXDE desktop. It is extremely light weight but has few features, (think notepad in windows).
Leafpad has very few features, most are under 'Options' in the top level menu including:
Leafpad also features Search and Replace, available under 'Search' in the top level menu. From here you can use find to 'find' specific text, or 'replace' to replace it.