set
ShellPackage: bash
Sets the shell's behaviour. set -euo pipefail at the top of a script stops it at the first failing command, the first undefined variable, and an error in the middle of a pipe — instead of carrying on as if nothing happened.
What its options do in the lessons
From the same glossary the lessons render under their commands, so the two cannot disagree.
set -e- Stops the script at the first command that fails, instead of carrying on from a false premise.
set -u- Treats the use of an unset variable as an error. A typo in a variable name becomes visible instead of meaning empty string.
set -o- Turns on a named shell option.
-o pipefailmakes a pipeline fail if any command in it fails, not just the last one.