Click on any of the 687 commands below to get a description and list of available options. All links in the command summaries point to the online version of the book on Safari Bookshelf.
flex (Fast Lexical Analyzer Generator) is a faster variant of lex. It generates a lexical analysis program (named lex.yy.c) based on the regular expressions and C statements contained in one or more input files. See also bison, yacc, and the O'Reilly book lex & yacc.
Options
-b
Generate backup information to lex.backup.
-d
Debug mode.
-f
Use a faster scanner. The result is larger but faster.
-h
Help summary.
-i
Scan case-insensitively.
-l
Maximum lex compatibility.
-o file
Write output to file instead of lex.yy.c.
-p
Print performance report.
-s
Exit if the scanner encounters input that does not match any of its rules.
-t
Print to standard output. (By default, flex prints to lex.yy.c.)
-v
Print a summary of statistics.
-w
Suppress warning messages.
-B
Generate batch (noninteractive) scanner.
-F
Use the fast scanner table representation. This option is usually as fast as -f and often generates smaller data (although for some data sets, it generates larger data).
-I
Generate an interactive scanner (default).
-L
Suppress #line directives in lex.yy.c.
-P prefix
Change default yy prefix to prefix for all globally visible variable and function names.
-V
Print version number.
-7
Generate a 7-bit scanner.
-8
Generate an 8-bit scanner (default).
-+
Generate a C++ scanner class.
-C
Compress scanner tables but do not use equivalence classes.
-Ca
Align tables for memory access and computation. This creates larger tables but gives faster performance.
-Ce
Construct equivalence classes. This creates smaller tables and sacrifices little performance (default).
-Cf
Generate full scanner tables, not compressed.
-CF
Generate faster scanner tables, like -F.
-Cm
Construct metaequivalence classes (default).
-Cr
Bypass use of the standard I/O library; use read( ) system calls instead.