Shell execution options
cmd1 && cmd2 && cmd3 equivalent to
The shell prints a message to stderr when it tries to expand a variable that is not set. Also it immediately exits. An interactive shell will not exit.
The shell prints each command in a script to stderr before running it.
set -o pipefail
Pipelines fail on the first command which fails instead of dying later on down the pipeline. This is especially good when cmd3 is a command that always succeeds (like echo):
cmd1 | cmd2 | cmd3