Simon Geard wrote:
>
> If the instructions aren't part of a script, what exactly does the "bash
> -e" step contribute? Start a new shell for running commands in, which
> should exit any time one of them fails? The -e might be useful in an
> shell script (i.e the #!/bin/bash case), but what's the point for an
> interactive shell?
Hmm, I see no indication in the man page that 'set -e' should be limited
to a non-interactive shell.
-e Exit immediately if a *simple command* (see SHELL GRAMMAR
above) exits with a non-zero status. The shell does not
exit if the command that fails is part of the command
list immediately following a while or until keyword,
part of the test in an if statement, part of a && or ??
list, or if the command's return value is being inverted
via !. A trap on ERR, if set, is executed before the
shell exits.
IMO a loop to handle repetitive tasks does not qualify as a 'script'.
Of course that is my opinion, but I guess if automating a task
constitutes a script, then we should review all the pipes and redirected
output in the book. ;-)
Seriously though, this is a perfect example of -e's use in an
interactive shell. I could have easily used three conditional breaks
and two conditional exits, but fortunately, ease of use was considered.
Besides, it might have looked too much like a script if I had done it
that way! ;-)
-- DJ Lucas
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