Script for converting Hexadecimal IP to Decimal IP

PKrishna · 07-04-2008, 12:57 PM

Dear All,

Could someone help me with some script to convert Hexadecimal IPs to Decimal dotted IPs please?
I have a file with 2600 Hex IPs of the following format

15 41 01 C2
15 41 01 C6
15 41 01 C7

Please help me convert them into the following format

21.65.1.194
21.65.1.198
21.65.1.199

Thanks in advance.

Warm regards,
Krishna

colucix · 07-04-2008, 01:57 PM

You can use bc specifying that the number is base-16, for example by something like

Code:

for i in 15 41 01 C2
do
  printf "%d." $(echo "ibase=16; $i" | bc)
done | sed s/.$//

The sed command serves to strip out the ending dot, but there should be a better way to do.

jschiwal · 07-04-2008, 02:25 PM

Code:

cat sample
15 41 01 C2
15 41 01 C6
15 41 01 C7

while read ip[0] ip[1] ip[2] ip[3]; do 
   for ((n=0; n<4; n++)); do 
      ip[(($n))]=$((0x${ip[$n]}))
   done
   echo "${ip[0]}.${ip[1]}.${ip[2]}.${ip[3]}"
done <sample

21.65.1.194
21.65.1.198
21.65.1.199

You might want to use something like
ipaddress="${ip[0]}.${ip[1]}.${ip[2]}.${ip[3]}" instead of an echo in a script. You could even write a similar routine as a function to take a string like "15 41 01 C2" and return a string like "21.65.1.194".

colucix · 07-04-2008, 04:11 PM

Following the suggestion by jschiwal, you can create a simple function like this:

Code:

hex2dec(){
  echo -n $(echo "ibase=16; $1" | bc).
  echo -n $(echo "ibase=16; $2" | bc).
  echo -n $(echo "ibase=16; $3" | bc).
  echo -n $(echo "ibase=16; $4" | bc)
}

or

Code:

hex2dec(){
  echo -n $((0x$1)).
  echo -n $((0x$2)).
  echo -n $((0x$3)).
  echo -n $((0x$4))
}

You can also include a check on the number and the type of the arguments. Thanks to jschiwal for pointing out the bash syntax to do the conversion. I didn't know it.

Mr. C. · 07-04-2008, 04:24 PM

Code:

$ cat ips

15 41 01 C2
15 41 01 C6
15 41 01 C7

$ perl -ne 'printf "%d.%d.%d.%d\n", map { hex($_)} split unless /^\s*$/' ips
21.65.1.194
21.65.1.198
21.65.1.199

jschiwal · 07-04-2008, 07:49 PM

Thanks for your contribution colucix. I made a small change and removed the "-n" option from the last echo statement.

Code:

cat bin/hex2decip
h2dip(){
  echo -n $((0x$1)).
  echo -n $((0x$2)).
  echo -n $((0x$3)).
  echo  $((0x$4))
}
jschiwal@hpamd64:~> source hex2decip
jschiwal@hpamd64:~> type hex2decip
hex2decip is /home/jschiwal/bin/hex2decip
jschiwal@hpamd64:~> type h2dip
h2dip is a function
h2dip ()
{
    echo -n $((0x$1)).;
    echo -n $((0x$2)).;
    echo -n $((0x$3)).;
    echo $((0x$4))
}
jschiwal@hpamd64:~> h2dip 12 1A 1b 22
18.26.27.34

I also included "ip" at the end of the name because it seems hex2dec is either taken or describes converting hexidecimal strings to their decimal equivalent. ( I think that DVD's use binary coded hex values, similar to bcd, for portability reasons. ) I also noticed how bash added the semicolons at the end of the statements. I hadn't noticed that before.