Which command is used for searching text within files?

The command used for searching text within files is "grep." This utility scans files for specific patterns or strings and outputs the lines that contain a match. It is particularly powerful due to its use of regular expressions, allowing users to perform complex searches for text patterns within files. Developers and system administrators frequently use grep for its efficiency in text searching and for analyzing logs, configuration files, or any kind of textual data.

The command operates in the following manner: when a user specifies a pattern, grep reads through the specified file(s) and checks each line to see if it contains that pattern, finally printing all lines that include the match. This makes it an invaluable tool in text processing and analysis in a Linux environment.