11. Macros for text handling

There are a number of builtins in m4 for manipulating text in various ways, extracting substrings, searching, substituting, and so on.

11.1 Calculating length of strings
11.2 Searching for substrings
11.3 Searching for regular expressions
11.4 Extracting substrings
11.5 Translating characters
11.6 Substituting text by regular expression
11.7 Formatting strings (printf-like)