sysread

sysread 
filehandle
, 
scalar
, 
length
, [
offset
]

Reads length bytes of data into variable scalar from the specified filehandle . The function returns the number of bytes actually read, or 0 at EOF. It returns the undefined value on error. scalar will grow or shrink to the length actually read. The offset , if specified, says where in the string to start putting the bytes, so that you can read into the middle of a string that's being used as a buffer. You should be prepared to handle the problems (like interrupted system calls) that standard I/O normally handles for you.