Discovered the New World
#!/bin/bash for (( i=1 ; i <= 225 ; i++ )) do nslookup 140.119.160.${i} | tail -2 | head -n 1 | grep "cs" >> n_host done 1.162.119.140.IN-ADDR.ARPA name = dns.cs.nccu.edu.tw. 3.162.119.140.IN-ADDR.ARPA name = test.cs.nccu.edu.tw. 10.162.119.140.IN-ADDR.ARPA name = meetingroom.cs.nccu.edu.tw. 11.162.119.140.IN-ADDR.ARPA name = venus.cs.nccu.edu.tw. 12.162.119.140.IN-ADDR.ARPA name = jupiter.cs.nccu.edu.tw. 18.162.119.140.IN-ADDR.ARPA name = clhan.cs.nccu.edu.tw. 23.162.119.140.IN-ADDR.ARPA name = sakura.cs.nccu.edu.tw. 25.162.119.140.IN-ADDR.ARPA name = ts.cs.nccu.edu.tw. 26.162.119.140.IN-ADDR.ARPA name = ts_2.cs.nccu.edu.tw. 27.162.119.140.IN-ADDR.ARPA name = ts27.cs.nccu.edu.tw. 28.162.119.140.IN-ADDR.ARPA name = ts28.cs.nccu.edu.tw. 29.162.119.140.IN-ADDR.ARPA ...