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Command: lex | Section: 1 | Source: UNIX v7 | File: lex.1
LEX(1) General Commands Manual 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 written in C to be executed when expres-
sions 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 executes the associated C action for each regular ex-
pression 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 ana-
lyzer.
-n Opposite of -v; -n is default.
-f `Faster' compilation: don't bother to pack the resulting tables;
limited to small programs.
SEE ALSO
yacc(1)
M. E. Lesk and E. Schmidt, LEX - Lexical Analyzer Generator
LEX(1)