I have a file called file.txt which contains either an IP or a FQDN, followed by ports that were found to be open. I want my bash script to prepend all ports with their associated IP/FQDN (always above them in the file), replace the forward slash with a whitespace, and then delete the IP/FQDN line that isn't associated with a port.

Breaking it down, I thought:

1. Read the next line
2. If the line contains a "." in it (IP or FQDN), prepend it into all following lines, unless:
3. If the following line has a "." in it (another IP or FQDN), make that line the new one to prepend and repeat the process for all following lines
4. Replace all "/" with a " " (one single whitespace)
5. Remove all lines that are not associated with a port (probably easier just to grep for "tcp" and "udp" as that will display all open ports with associated IP/FQDN

To make it easier, I can easily create a tmp file if necessary within the process. I have tried various iterartions of "while" and "if" and nothing seems to work...!

E.g:

cat file.txt

www.thisisawebsite.com:
80/tcp
443/tcp
500/udp
192.168.1.5:
80/tcp
dev.anothersite.co.uk:
22/tcp
443/tcp
5050/udp
21000/tcp
10.10.10.10:
4000/udp
8000/udp

Then, running the bash script, it should become:

www.thisisawebsite.com:80 tcp
www.thisisawebsite.com:443 tcp
www.thisisawebsite.com:500 udp
192.168.1.5:80 tcp
dev.anothersite.co.uk:22 tcp
dev.anothersite.co.uk:433 tcp
dev.anothersite.co.uk:5050 udp
dev.anothersite.co.uk:21000 tcp
10.10.10.10:4000 udp
10.10.10.10:8000 udp

Thanks for any help.

CodePudding user response：

Looks like a job for awk:

awk -F/ '/\./ {d=$0; next} {print d":"$1, $2}'