[color=blue]-(dearvoid@LinuxEden:tty3)-(~/void/lex_yacc)-
[4140 0][/color] [color=red]; cat cat.l
[/color]
%%

        // The following 2 lines may be removed.
.       ECHO;   // #define ECHO fwrite(yytext, yyleng, 1, yyout)
\n      ECHO;

%%

int main()
{
    yylex();
    return 0;
}
[color=blue]-(dearvoid@LinuxEden:tty3)-(~/void/lex_yacc)-
[4140 0][/color] [color=red]; flex -o cat.c cat.l
[/color][color=blue]-(dearvoid@LinuxEden:tty3)-(~/void/lex_yacc)-
[4140 0][/color] [color=red]; gcc -o cat cat.c -ll
[/color]cat.c:1017: warning: ‘yyunput’ defined but not used
[color=blue]-(dearvoid@LinuxEden:tty3)-(~/void/lex_yacc)-
[4140 0][/color] [color=red]; ./cat
[/color]hello
hello
world
world
[color=blue]-(dearvoid@LinuxEden:tty3)-(~/void/lex_yacc)-
[4140 0][/color] [color=red]; o
[/color]