Most operating systems come equipped with some kind of local search engine. Users can fire it up with some keyboard shortcut and then just enter what local file they are looking for.
Before such features came up, command-line users already searched through files with tools such as grep or awk. The user can simply type "grep -r foobar ." and the tool will crawl recursively through the current directory and find any file that contains the "foobar" string.
In this recipe, we will implement exactly such an application. Our little grep clone will just accept a pattern from the command line, and then recursively search through the directory we are in at the time of the application start. It will then print the name of every file that matches our pattern. The pattern matching will be applied linewise, so we can also print...
