read and write

• SYNOPSIS
  ssize_t read(int fd, void *buf, size_t count);
  ssize_t write(int fd, const void *buf, size_t count);
• DESCRIPTION
  read() attempts to read up to count bytes from file descriptor fd into the buffer starting at buf. write() writes up to count bytes to the file referenced by the file descriptor fd from the buffer starting at buf.
• RETURN VALUE
  On success of read, the number of bytes read is returned. It is not an error if this number is smaller than the number of bytes requested. On success of write, the number of bytes written are returned. On error of read and write, -1 is returned, and errno is set appropriately.
• ERRORS