man pages section 1: User Commands

Exit Print View

Updated: July 2014

flex (1)


flex - the fast lexical analyser generator


flex [OPTIONS] [FILE]...


User Commands                                             FLEX(1)

     flex - the fast lexical analyser generator

     flex [OPTIONS] [FILE]...

     Generates programs that perform pattern-matching on text.

  Table Compression:
     -Ca, --align
          trade off larger tables for better memory alignment

     -Ce, --ecs
          construct equivalence classes

     -Cf  do not compress tables; use -f representation

     -CF  do not compress tables; use -F representation

     -Cm, --meta-ecs
          construct meta-equivalence classes

     -Cr, --read
          use read() instead of stdio for scanner input

     -f, --full
          generate fast, large scanner. Same as -Cfr

     -F, --fast
          use alternate table representation. Same as -CFr

     -Cem default compression (same as --ecs --meta-ecs)

     -d, --debug
          enable debug mode in scanner

     -b, --backup
          write backing-up information to lex.backup

     -p, --perf-report
          write performance report to stderr

     -s, --nodefault
          suppress default rule to ECHO unmatched text

     -T, --trace
          flex should run in trace mode

     -w, --nowarn
          do not generate warnings

flex 2.5.35         Last change: February 2008                  1

User Commands                                             FLEX(1)

     -v, --verbose
          write summary of scanner statistics to stdout

     -o, --outfile=FILE
          specify output filename

     -S, --skel=FILE
          specify skeleton file

     -t, --stdout
          write scanner on stdout instead of lex.yy.c

          name of C++ class

          create a C header file in addition to the scanner

     --tables-file[=FILE] write tables to FILE

  Scanner behavior:
     -7, --7bit
          generate 7-bit scanner

     -8, --8bit
          generate 8-bit scanner

     -B, --batch
          generate batch scanner (opposite of -I)

     -i, --case-insensitive
          ignore case in patterns

     -l, --lex-compat
          maximal compatibility with original lex

     -X, --posix-compat
          maximal compatibility with POSIX lex

     -I, --interactive
          generate interactive scanner (opposite of -B)

          track line count in yylineno

  Generated code:
     -+,  --c++
          generate C++ scanner class

          #define macro defn  (default defn is '1')

flex 2.5.35         Last change: February 2008                  2

User Commands                                             FLEX(1)

     -L,  --noline
          suppress #line directives in scanner

     -P,  --prefix=STRING
          use STRING as prefix instead of "yy"

     -R,  --reentrant
          generate a reentrant C scanner

          scanner for bison pure parser.

          include yylloc support.

          initialize yyin/yyout to stdin/stdout

     --noansi-definitions old-style function definitions

          empty parameter list in prototypes

          do not include <unistd.h>

          do not generate a particular FUNCTION

     -c   do-nothing POSIX option

     -n   do-nothing POSIX option


     -h, --help
          produce this help message

     -V, --version
          report flex version

     See   attributes(5)   for   descriptions  of  the  following

flex 2.5.35         Last change: February 2008                  3

User Commands                                             FLEX(1)

     |Availability   | developer/lexer/flex |
     |Stability      | Volatile             |
     The full documentation for flex is maintained as  a  Texinfo
     manual.    If  the  info  and  flex  programs  are  properly
     installed at your site, the command

          info flex

     should give you access to the complete manual.

     This  software  was   built   from   source   available   at    The  original
     community   source   was   downloaded   from    http://soft-

     Further information about this software can be found on  the
     open   source   community   website  at  http://flex.source-

flex 2.5.35         Last change: February 2008                  4