Re: how to reverse an IPv4

[Lee <ler762@gmail.com>]

On 4/30/23, coreyh@free.fr <coreyh@free.fr> wrote:
> Hello list,
>
> I wrote this script for reversing an IP:
>
> #!/bin/bash
>
> IP=$1
>
> if [ -z $IP ];then
>    echo "$0 IP"
>    exit 1
> fi
>
> REVERSE=$(echo $IP|awk -F\. '{print $4.$3.$2.$1}')
> echo $REVERSE
>
>
> it won't work as the output below.
>
> $ bin/rbl.sh 61.144.56.32
> 325614461
>
>
> The "." was lost.
>
> If I changed the awk line to:
> REVERSE=$(echo $IP|awk -F\. '{print "$4.$3.$2.$1"}')
>
>
> It becomes:
>
> $ bin/rbl.sh 61.144.56.32
> $4.$3.$2.$1
>
>
>
> Can you help with this?

$ cat /tmp/reverse
#!/bin/bash

IP=$1

if [ -z $IP ];then
  echo "$0 IP"
  exit 1
fi

REVERSE=$(echo $IP|awk -F\. '{printf("%s.%s.%s.%s\n", $4, $3, $2, $1) }')
echo $REVERSE

$ /tmp/reverse 61.144.56.32
32.56.144.61

Regards
Lee