How to print a range of IP addresses with Linux seq command

Question

How can I print a range of ip addresses on linux command line using the "seq" command? For eg: I need seq to print a range of ip from 10.0.0.1 to 10.0.0.23 . Seems like the period in between the octets causes the number to behave like a floating point . I am getting a "invalid floating point argument error" . I tried using the -f option . May be I am not using it correctly. But it still gave me an error. I am trying to something similar to

seq 10.0.0.2 10.0.0.23

Is there another way to print IP addresses in a range in Linux other than switching over to excel ?

Answer 1

Use a format:

$ seq -f "10.20.30.%g" 40 50
10.20.30.40
10.20.30.41
10.20.30.42
10.20.30.43
10.20.30.44
10.20.30.45
10.20.30.46
10.20.30.47
10.20.30.48
10.20.30.49
10.20.30.50

Unfortunately this is non-obvious as GNU doesn't like to write man pages.

Answer 2

There is the prips utility which generates an IP list from a range or CIDR. Useful for work with large ranges:

$ prips 10.0.0.20 10.0.0.23
10.0.0.20
10.0.0.21
10.0.0.22
10.0.0.23

$ prips 10.0.0.0/23
10.0.0.0
10.0.0.1
10.0.0.2
<...>
10.0.1.254
10.0.1.255

Answer 3

You can use sed command with seq to print range of IP address.

seq 2 23 | sed 's/^/10.0.0./'

OR using echo and tr

echo 10.0.0.{2..23} | tr ' ' '\n'

Answer 4

The printf command performs implicit iteration if it is given more arguments than conversion specifiers. For example:

$ printf "%s-%s\n" 1 2 3 4 5 6
1-2
3-4
5-6

There are two conversions, but six arguments. So three repetitions of the formatting logic occur, marching over the arguments pairwise.

With that we can do:

printf "10.0.0.%s\n" $(seq 1 23)

The printf command, and its repeating behavior, are POSIX standard: "The format operand shall be reused as often as necessary to satisfy the argument operands." On the other hand, the seq command isn't.

Answer 5

for i in $(seq 2 23); do echo "10.0.0.$i"; done

Answer 6

If we remove the requirement to use the seq command, and assume that the ipcalc command is available, and the Ubuntu prips command is not, then prips can be implemented as a Bash shell function:

prips() {
  cidr=$1

  # range is bounded by network (-n) & broadcast (-b) addresses.
  lo=$(ipcalc -n $cidr |cut -f2 -d=)
  hi=$(ipcalc -b $cidr |cut -f2 -d=)

  read a b c d <<< $(echo $lo |tr . ' ')
  read e f g h <<< $(echo $hi |tr . ' ')

  eval "echo {$a..$e}.{$b..$f}.{$c..$g}.{$d..$h}"
}

Note that this will include the network address and broadcast address in the range; if that is a problem, delete the first and last address from the result.