;Rename a File 
.model small
.stack 100h
.data
         oldfn db'hello1.txt',0
         newfn db'welcome1.txt',0
         ok db 'File renamed$'
         notok db 'Error!File not renamed$'
.code
begin:  mov ax,@data
        mov ds,ax
        mov es,ax
        mov dx,offset oldfn
        mov di,offset newfn
        mov ah,56h
        int 21h
        jc error
        mov dx,offset ok
        jmp over
Error : mov dx,offset notok
over  : mov ah,09h
        int 21h
        mov ah,4ch
        int 21h
        end begin