Seven Surprising Bash Variables
1) PROMPT_COMMAND
2) HISTTIMEFORMAT
3) CDPATH
See comment:
https://unix.stackexchange.com/questions/456866/how-can-i-suppress-printing-the-full-path-to-subdirectories-when-using-cdpath/456867#456867
4) SHLVL
5) LINENO
6) REPLY
7) TMOUT
May 20, 2019 at 9:49:55 AM EDT
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FILLER