BSD 2.11 - man page for lex (bsd section 1)

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LEX(1)											   LEX(1)

NAME
       lex - generator of lexical analysis programs

SYNOPSIS
       lex [ -tvfn ] [ file ] ...

DESCRIPTION
       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 writ-
       ten in C to be executed when expressions are found.

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

	      cc lex.yy.c -ll

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

       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 analyzer.

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

       -f     "Faster" compilation: don't bother to pack the resulting tables; limited	to  small
	      programs.

EXAMPLE
	      lex lexcommands

       would draw lex instructions from the file lexcommands, and place the output in lex.yy.c

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

       is  an  example	of a lex program that would be put into a lex command file.  This program
       converts upper case to lower, removes blanks at the end of lines,  and  replaces  multiple
       blanks by single blanks.

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

7th Edition				  April 14, 1986				   LEX(1)
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