For installation instructions see the Section called Installing Flex-2.5.4a in Chapter 6.
Flex (2.5.4a):
ftp://ftp.gnu.org/non-gnu/flex/
The Flex package is used to generate programs which recognize patterns in text.
Installed programs: flex, flex++ (link to flex) and lex
Installed library: libfl.a
flex is a tool for generating programs that recognize patterns in text. Pattern recognition is useful in many applications. From a set of rules on what to look for flex makes a program that looks for those patterns. The reason to use flex is that it is much easier to specify the rules for than to write the actual pattern-finding program.
flex++ invokes a version of flex that is used exclusively for C++ scanners.
libfl.a is the flex library.
Flex depends on: Bash, Binutils, Bison, Coreutils, Diffutils, GCC, Gettext, Glibc, Grep, M4, Make, Sed.