man(1) Manual page archive

     LEX(1)                                                     LEX(1)

          lex - generator of lexical analysis programs

          lex [ -tvfn ] [ file ] ...

          Lex generates programs to be used in simple lexical analyis
          of text.  The input files (standard input default) contain
          regular expressions to be searched for, and actions written
          in C to be executed when expressions are found.

          A C source program, `lex.yy.c' is generated, to be compiled

               cc lex.yy.c -ll

          This program, when run, copies unrecognized portions of the
          input to the output, and executes the associated C action
          for each regular expression that is recognized.

          The following lex program converts upper case to lower,
          removes blanks at the end of lines, and replaces multiple
          blanks by single blanks.

               [A-Z] putchar(yytext[0]+'a'-'A');
               [ ]+$
               [ ]+  putchar(' ');

          The options have the following meanings.

          -t   Place the result on the standard output instead of in
               file `lex.yy.c'.

          -v   Print a one-line summary of statistics of the generated

          -n   Opposite of -v; -n is default.

          -f   `Faster' compilation: don't bother to pack the result-
               ing tables; limited to small programs.

          yacc(1), sed(1)
          M. E. Lesk and E. Schmidt, LEX - Lexical Analyzer Generator