How to determine how many shells deep I might be?
Solution 1:
echo $SHLVL
From the bash manpage:
SHLVL Incremented by one each time an instance of bash is started.
Solution 2:
One way is to use pstree:
$ pstree -h
[...]
├─sshd─┬─sshd───sshd───bash───bash───bash───bash───bash───pstree
│ └─sshd───sshd───bash───bash───bash───bash
[...]