Netmask - IP network calculation utility

網段計算工具 netmask (備用載點)
很好用!

# netmask --help

This is netmask, an address netmask generation utility

Usage: netmask spec [spec ...]

  -h, --help                    Print a summary of the options

  -v, --version                 Print the version number

  -d, --debug                   Print status/progress information

  -s, --standard                Output address/netmask pairs

  -c, --cidr                    Output CIDR format address lists

  -i, --cisco                   Output Cisco style address lists

  -r, --range                   Output ip address ranges

  -x, --hex                     Output address/netmask pairs in hex

  -o, --octal                   Output address/netmask pairs in octal

  -b, --binary                  Output address/netmask pairs in binary

  -n, --nodns                   Disable DNS lookups for addresses

Definitions:

  a spec can be any of:

    address

    address:address

    address:+address

    address/mask

  an address can be any of:

    N           decimal number

    0N          octal number

    0xN         hex number

    N.N.N.N     dotted quad

    hostname    dns domain name

  a mask is the number of bits set to one from the left

# netmask -r 192.168.0.0/28

    192.168.0.0-192.168.0.15    (16)

# netmask -s 192.168.0.0/28

    192.168.0.0/255.255.255.240