Ubuntu Unleashed 2013 Edition: Covering 12.10 and 13.04, Eighth Edition

Searches for a String in Input with grep

The grep command, like find, is an incredibly powerful search tool in the right hands. Unlike find, though, grep processes any text, whether in files, or just in standard input.

The basic usage of grep is this:

matthew@seymour:~$ grep "some text" *

That searches all files in the current directory (but not subdirectories) for the string some text and prints matching lines along with the name of the file. To enable recursive searching in subdirectories, use the -r parameter, as follows:

matthew@seymour:~$ grep -r "some text" *

Each time a string is matched within a file, the filename and the match are printed. If a file contains multiple matches, each of the matches is printed. You can alter this behavior ...