I am currently playing CTF in OverTheWire website . I was stuck on 32nd Level [ https://overthewire.org/wargames/bandit/bandit33.html ] to get password for next Level . Command to access Level 32 -
ssh email@example.com -p 2220 and the password is
SO when I login I get made up shell called UPPERCASE SHELL . Which takes commands and converts them to UPPERCASE throwing "command not found error " . When I run $SHELL , all I can see is a banner called "WELCOME TO UPPERCASE SHELL" . So I googled for walk-through after being stuck on for 3 hours . SO one of the guy enterd $0 which took him to Bourne Shell [ I guess ] . SO what is the difference between $0 and $SHELL .
By my understanding $SHELL is default shell [ UPPERCASE_SHELL ] which I verified after running
cat /etc/paswd | grep bandit32 . SO what is $0 . If $0 is current shell then I should get the same banner[ UpperCase ] as output . How come I landed Bourne Shell .
Bottom line . what are these 2 shell variables how do thesework in this context ?