I observe this issue below:
abc@ubuntu:~$ sudo - i [sudo] password for abc: sudo: -: command not found abc@ubuntu:~$ sudo -i root@ubuntu:~#
sudo command seems to fail with error "command not found", however for next
sudo attempt with correct option, it got root login but this time it didn't ask for password. Why this strange behavior?
I am asking this question from security view of point. Notice that after "command not found" the user is still "abc" which may not be admin. He/She can get the "root" privileges without even knowing the sudo password by simply issuing "sudo -i" within 15 minutes(cached password time). Isn't it?