PT[101]% ls hello.l typescript PT[102]% flex hello.l PT[103]% ls hello.l lex.yy.c typescript PT[105]% gcc lex.yy.c Undefined symbols: "_yywrap", referenced from: _yylex in ccoutww1.o _input in ccoutww1.o ld: symbol(s) not found collect2: ld returned 1 exit status PT[106]% gcc lex.yy.c -ll PT[107]% ls a.out* hello.l lex.yy.c typescript PT[108]% ./a.out Hi [BLINK, BLINK] Hello Hi! How are you doing? Good. Hey there! Hey yourself! G'day mate! [BLINK, BLINK] Good morning [BLINK, BLINK] Bonjour [BLINK, BLINK] quit PT[109]%