Depeche View loads all text files from a folder into memory, allowing instant search as you type. Search a word or phrase just by clicking on it. Copy phrases or lines to clipboard by Control+Click.
Create bookmarks by Alt+Click (Control+RightClick under Linux). Integrate with your favorite editor through self-defined commands on function keys.
Under Windows, drag+drop folders from explorer onto the tool, or run it through double-click, then click on Open and select a folder containing many text files. Alternatively, open a command line and type "dview dirname".
Both ways will run Depeche View. The tool will load all text files from the given directory, and all subdirectories, and display their contents in one large window.