On 1/11/23 4:04 PM, Quinn Grier wrote:
On 2023-01-11 06:44, Chet Ramey wrote:
On 1/10/23 9:36 PM, Quinn Grier wrote:
In the documentation for set -e, the Bash manual says that errexit is
suspended in all but the last command of a pipeline:
The shell does not exit if the command that fails is part of
[...] any command in a pipeline but the last
I'm not sure why you included the `part of' in your quote, since it clearly
applies to the text following it: "part of the command list immediately
following as while or until keyword, part of the test following ..."
I agree, my quotation of that documentation is wrong, as "part of" does
not apply to "any command in a pipeline". However, I still think my
example script shows something fishy.
Here's another example script that might help show what I mean. This one
goes through all of the apparent contexts where set -e is ignored:
They are not all contexts where set -e is ignored. There is a distinction
between the effect of -e being ignored and the shell not exiting when a
command fails.
If you don't like the bash manual page wording, here's what POSIX says:
"1. The failure of any individual command in a multi-command pipeline
shall not cause the shell to exit. Only the failure of the pipeline itself
shall be considered.
2. The -e setting shall be ignored when executing the compound list
following the while, until, if, or elif reserved word, a pipeline beginning
with the ! reserved word, or any command of an AND-OR list other than the last.
3. If the exit status of a compound command other than a subshell
command was the result of a failure while -e was being ignored, then -e
shall not apply to this command.
This requirement applies to the shell environment and each subshell
environment separately. For example, in:
set -e; (false; echo one) | cat; echo two
the false command causes the subshell to exit without executing echo one;
however, echo two is executed because the exit status of the pipeline
(false; echo one) | cat is zero."
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU c...@case.edu http://tiswww.cwru.edu/~chet/
