06-19-2006
Hi,
In Unix-like operating systems, "/dev/null" or "the null device" is a special file that discards all data written to it, and provides no data to any process that reads from it (it returns EOF).
The null device is typically used for disposing of unwanted output streams of a process, or as a convenient empty file for input streams. This is usually done by redirection.
Best Regards,
Sridhar M
Quote:
Originally Posted by rrs
hello all,
In many shell scripts i found '> /dev/null' , i am not able to get this,
will any one please explain why we are using this.
thanks
sudha
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null(n) null(n)
__________________________________________________________________________________________________________________________________________________
NAME
null - Create and manipulate null channels
SYNOPSIS
package require Tcl
package require memchan
null
_________________________________________________________________
DESCRIPTION
The command described here is only available in a not-yet released version of the package. Use the CVS to get the sources.
null creates a null channel which absorbs everything written into it. Reading from it is not possible, or rather will always return zero
bytes. These channels are essentially Tcl-specific variants of the null device for unixoid operating systems (/dev/null). Transfer-
ing the generated channel between interpreters is possible but does not make much sense.
OPTIONS
Memory channels created by null provide one additional option to set or query.
-delay ?milliseconds?
A null channel is always writable and readable. This means that all fileevent-handlers will fire continuously. To avoid starvation
of other event sources the events raised by this channel type have a configurable delay. This option is set in milliseconds and
defaults to 5.
A null channel is always writable and never readable. This means that a writable fileevent-handler will fire continuously and a readable
fileevent-handler never at all. The exception to the latter is only the destruction of the channel which will cause the delivery of an eof
event to a readable handler.
SEE ALSO
fifo, fifo2, memchan, random, zero
KEYWORDS
channel, i/o, in-memory channel, null
COPYRIGHT
Copyright (c) 1996-2003 Andreas Kupries <andreas_kupries@users.sourceforge.net>
Memory channels 2.2 null(n)