The great thing about this game is that whoever knows UUoC will be the winner.
cat file.txt | tr a-z A-Z | sort (loser)
tr < file.txt a-z A-Z | sort (winner!)
8 karma · joined March 9, 2019
cat file.txt | tr a-z A-Z | sort (loser)
tr < file.txt a-z A-Z | sort (winner!)
Its behaviour is a common behaviour of all sh, not just Bash.
https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1...
POSIX omits from standardisation what is not necessary for an application to work, so that a wide range of systems can be supported. As for Shebang, it can be rewritten in the installation script and is therefore considered an area of system administration.
ShellSpec (https://shellspec.info/) is a POSIX compliant testing framework supports all POSIX shells (Bash >= 2.0, dash, ksh88, zsh >=3.1, etc). I'm the author of ShellSpec.