18
libraries
from
GNU
operating
system,
developed by
Linus
Torvalds.
Now
Linux
is
developed
under
GNU
Public
License.
Many
Linux
distributions
are
open
source
and
developed not limited to a company or community.
Linux
itself
is
the core of
the operating system,
usually known
as
Linux kernel.
Kernel’s
function
is
as
a
core
program
to
run
and
stop
processes,
start
and
end
other
programs, handle
memory requests,
access
disks
and
drives,
and
manage
network
connections, as
well
as
to
manage
hardware
resources
and
software
drivers.
All
distributions use
the
exact
typical
kernel.
Linux
kernel
adopts
the
monolithic
kernel
architecture, where
the
kernel
handles
all
services
on
top
of
all
hardware,
modules,
system
calls,
and
other
services.
The
kernel
also
operates
separately with
the
user
interface. This
makes
the Linux
system
more stable when user applications
fail and does
not affect the core system. One of
most generally acknowledged Linux operating system
is
the
Fedora
Core
Linux
distribution,
a
development of
Red
Hat
version.
I
prefer
the
Fedora Core 7 which is available to use.
2.1.4.2 UNIX Shell
The shell
is
the UNIX
command processor.
The shell
interprets every command
that
is
typed by the
users or administrators and
it
will
take
appropriate action.
Basically
commands are entered with standard
input on keyboard, read by the shell, and the results
of
the
interpretation come
out
either
in
standard output or
standard error.
Both
standard
output and standard error are shown
from
the terminal
screen. The
most commonly
used
shell in UNIX is the Bourne Shell family, which is comprised of Bourne Shell (sh), Korn
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