How i can grep only subdomain names without "target.com" [closed]

Question

i have w wordlist of subdomains contains like this :

admin.bugbountytarget.com
portal.bugbountytarget.com
sales.bugbountytarget.com
vpn1.bugbountytarget.com
dev.test.bugbountytarget.com
...

And I want to grep subdomains names without ".bugbountytarget.com" Only:

admin
portal
sales
...

Thank you.

Answer 1

With grep specifically (assuming it is compiled with libpcre):

grep -Po '^.*\b(?=\.bugbountytarget\.com$)' domainlist.txt

This just looks for the target at the end, in a forward lookahead (not a part of the match) and then prints the match.

With awk, no regular expressions needed (faster but you'll only notice with a massive file):

awk 'index($0, ".bugbountytarget.com") == length($0) - 19 {
  print substr($0, 1, length($0) - 20)
}' domainlist.txt

This looks for a substring (the target domain), ensures it's at the end of the line, then prints it without the target. Lengths matter.

With sed:

sed '/\.bugbountytarget\.com$/!d; s///' domainlist.txt

This finds lines that end with a literal .bugbountytarget.com and then it substitutes that last match with an empty string and prints that out.