lex.c

一个shell程序可以实现管道

%{
int _numargs = 10;
char *_args[10];
int _argcount = 0;
%}

QUOTE \"[^\"]*\"
WORD	[a-zA-Z0-9\/\.-]+
SPECIAL	[()><|&;*]

%%
	_argcount = 0;
	_args[0] = NULL;

{QUOTE}|{WORD}|{SPECIAL} {
	  if(_argcount < _numargs-1) {
	    _args[_argcount++] = (char *)strdup(yytext);
	    _args[_argcount] = NULL;
	  }
	}

\n	return (int)_args;

[ \t]+

.

%%

char **getline() {
  return (char **)yylex();
}

int yywrap(){
	return 0;
}