A simple way to calculate IP information

发现个命令比较有意思 [ipcalc] ,原来没注意过.

# man ipcalc

IPCALC(1)                                                       RH                                                      IPCALC(1)

NAME
       ipcalc - perform simple manipulation of IP addresses

SYNOPSIS
       ipcalc [OPTION]... [/prefix] [netmask]

DESCRIPTION
       ipcalc  provides a simple way to calculate IP information for a host.  The various options specify what information ipcalc
       should display on standard out. Multiple options may be specified.  An IP address to operate on must always be  specified.
       Most operations also require a netmask or a CIDR prefix as well.

OPTIONS
       -b, --broadcast
              Display the broadcast address for the given IP address and netmask.

       -h, --hostname
              Display the hostname for the given IP address.

       -m, --netmask
              Calculate  the netmask for the given IP address. It assumes that the IP address is in a complete class A, B,
              or C network. Many networks do not use the default netmasks, in which case an inappropriate  value  will  be
              returned.

       -p, --prefix
              Show the prefix for the given mask/IP address.

       -n, --network
              Display the network address for the given IP address and netmask.

       -s, --silent
              Don't ever display error messages.

AUTHORS
       Erik Troan <>
       Preston Brown <>

REPORTING BUGS
       Report bugs to our bugtracking system: .

COPYRIGHT
       Copyright ?1997-2001 Red Hat, Inc.
       This  is  free software; see the source for copying conditions.  There is NO warranty; not even for MERCHANTABILITY
       or FITNESS FOR A PARTICULAR PURPOSE.

Red Hat, Inc.                                             April 30 2001                                                 IPCALC(1)