Unix Interview Questions and Answers

 

What are the Unix system calls for I/O?

open(pathname,flag,mode) - open file



creat(pathname,mode) - create file



close(filedes) - close an open file



read(filedes,buffer,bytes) - read data from an open file



write(filedes,buffer,bytes) - write data to an open file



lseek(filedes,offset,from) - position an open file



dup(filedes) - duplicate an existing file descriptor



dup2(oldfd,newfd) - duplicate to a desired file descriptor



fcntl(filedes,cmd,arg) - change properties of an open file



ioctl(filedes,request,arg) - change the behaviour of an open file



The difference between fcntl anf ioctl is that the former is intended for any open
file, while the latter is for device-specific operations.

Posted by:Richards