scas demo

        org 100h

start:

;greeting:
 ;       mov     ah, $09
        ;mov     dx, greeting
  ;      int 21h

comparison:
        mov     ax, 'e'
        mov     di, text
        repne   scasb
        jne     not_found

        found:
        mov     ah, $09
        mov     dx, ansYes
        int 21h
        jmp exit

        not_found:
        mov     ah, $09
        mov     dx, ansNo
        int 21h
        jmp exit

exit:
        mov     ah, $09
        mov     dx, press_any_key
        int 21h
        mov     ah, $08
        int 21h
        ret

text            db "Gotta guys$"
;greeting        db "Hello!", 13, 10, "$"
inputString     db 11, 0, 10 dup (?)
nextLine        db 13, 10, "$"
ansYes          db "Yes!", 13, 10, "$"
ansNo           db "No!", 13, 10, "$"
press_any_key     db 13, 10, "Press any key to exit...$"