On 6/8/19 3:41 PM, _...@crans.org wrote:
> Bash Version: 5.0
> Patch Level: 7
> Release Status: release
>
> Description:
> When `eval` runs "set -o history", subsequent lines in the
> eval-ed string are recorded in the history.
Yes. History doesn't require an interactive shell to work; you can save
commands in the history list and use the history commands to operate on
them in any shell that runs `set -o history'.
>
> This breaks the following coding pattern:
> saved_options="$(set +o)" # save shell options
> ... # do some things with custom shell options
> eval "$saved_options" # restore shell options
> Indeed, if history is enabled (which is very likely), then the
> output of "set +o" will include the line "set -o history",
> followed by lines for enabling or disabling other options, and
> these following lines pollute the user’s history.
>
> What makes me think it is an actual bug is that when the
> "history" option was already enabled, "set -o history" should
> have no effect; yet lines before are not recorded, and lines
> after are recorded.
Bash temporarily stops recording commands in the history when you use
`eval', but if you turn history back on explicitly using `set -o history',
it will honor that.
--
``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/
