Search inside (plain text) files in Windows Explorer using content keywords
Pressing F3 in Windows Explorer will let you filter a folder excluding files the names of which won’t conform with your keyword. However some times, when you are in folders containing simple text documents (txt, html, asp, php, xml, etc) you may like to filter the contents of such folders not only or even not at all by file name, but by a word that must be present in the text inside your files.
You can use powerful freeware utilities such as V-Grep that will let you search your files for keywords, combining also more criteria, if needed, even getting for you immediately the context (some lines above and below the line of the keyword). However, if you just need to filter the files of a folder just by the presence of a keyword inside the files, you can do it easily in Windows Explorer itself without using any other utility.
F3 will get your cursor inside Windows Explorer search box, where you can write “contents:” (without the quotes) followed by the keyword (or part of it) you are looking for. For example, if you need a list of files in a folder and its subfolders that contain the word “freeware”, press F3 and in the search box of Windows Explorer write, contents: freeware