read

Reads _length_ bytes from ARGF. The files named on the command line
are concatenated and treated as a single file by this method, so when
called without arguments the contents of this pseudo file are returned in
their entirety.

_length_ must be a non-negative integer or nil. If it is a positive
integer, +read+ tries to read at most _length_ bytes. It returns nil
if an EOF was encountered before anything could be read. Fewer than
_length_ bytes may be returned if an EOF is encountered during the read.

If _length_ is omitted or is _nil_, it reads until EOF. A String is
returned even if EOF is encountered before any data is read.

If _length_ is zero, it returns _""_.

If the optional _outbuf_ argument is present, it must reference a String,
which will receive the data.
The <i>outbuf</i> will contain only the received data after the method call
even if it is not empty at the beginning.

   $ echo "small" > small.txt
   $ echo "large" > large.txt
   $ ./glark.rb small.txt large.txt

   ARGF.read      #=> "small\nlarge"
   ARGF.read(200) #=> "small\nlarge"
   ARGF.read(2)   #=> "sm"
   ARGF.read(0)   #=> ""

Note that this method behaves like fread() function in C.  If you need the
behavior like read(2) system call, consider +ARGF.readpartial+.