On Thu, Feb 17, 2022 at 12:50 PM Michael Conrad <mcon...@intellitree.com> wrote:
>
> On 2/16/22 19:32, Kang-Che Sung wrote:
> >
> >> Now, for an example where it makes a difference. Consider a Bash script
> >> like this:
> >>
> >> # enable automatic error handling
> >> set -eo pipefail
> >> # check for string "issues" in a logfile
> >> cat logfile | grep issue | sort --unique
> >>
> >> If there are no issues in the logs, grep return exit code 1 and the
> >> shell interprets this as an error and exits itself.
> >>
> > Why do we need to implement a workaround in grep while you can
> > do this in shell to ignore the exit code of grep?
> >
> > { grep issue <logfile || :; } | sort --unique
>
> In order to implement his suggestion, you need to only ignore exit code
> 1, while still allowing other exit codes to abort the script. (like a
> system error while reading the file)
{ grep issue <logfile || if [ "$?" -eq 1 ]; then true; fi; } | sort --unique
> But also, I've never seen ":" used as a command... where is that
> documented? Is it equivalent to 'true'?
https://www.gnu.org/savannah-checkouts/gnu/autoconf/manual/autoconf-2.71/html_node/Limitations-of-Builtins.html
Look for the "true" section.
_______________________________________________
busybox mailing list
busybox@busybox.net
http://lists.busybox.net/mailman/listinfo/busybox
