On 4/4/17 5:08 PM, nesro wrote:
>
> To have both commands similar, let's assume the while as this:
>
> while (( 1 > 2 )); do :; done
>
> Thanks for explaining me why it happen, but now I don't know why for cycle
> works and while does not.
When extdebug is enabled, the command is skipped if the DEBUG trap returns
non-zero. This doesn't change $? (traps never do) and it doesn't cause the
command that would have been run to return a non-zero exit status. If it
did, the combination of DEBUG and `set -e' would exit the shell, for
example, and I'm sure it would not behave as the bash debugger would
expect. For that matter, why should a command that's not run fail?
Since that command returns successfully, when it's used as the `while'
command test, it causes the while command to execute forever.
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU c...@case.edu http://cnswww.cns.cwru.edu/~chet/
