hping
Command-line oriented TCP/IP packet assembler and analyzer.
TLDR
Ping localhost over TCP
$ hping3 [localhost]
Ping an IP address over TCP on a specific port
$ hping3 -p [80] -S [192.168.1.1]
Ping an IP address over UDP on port 80
$ hping3 --udp -p [80] -S [192.168.1.1]
Scan a set of TCP ports on a specific IP address
$ hping3 --scan [80,3000,9000] -S [192.168.1.1]
Perform a charge test on port 80
$ hping3 --flood -p [80] -S [192.168.1.1]