Re: [PATCH] maintenance: specify explicit stdin for crontab

On 3/30/2021 1:12 PM, Kevin Daudt wrote:

On Tue, Mar 30, 2021 at 08:02:22AM -0400, Derrick Stolee wrote:

quoted

On 3/30/2021 1:41 AM, Martin Ågren wrote:

quoted

On Mon, 29 Mar 2021 at 23:23, Kevin Daudt [off-list ref] wrote:

quoted

There are multiple crontab implementations that require stdin for
editing a crontab to be explicitly specified as '-'.

Thank you for reporting this, especially with a patch!

However, I'm not sure about this adding of '-' being something that
crontab ignores so commonly. My Ubuntu machine reports this:

$ crontab -e -
crontab: usage error: no arguments permitted after this option
usage:  crontab [-u user] file
        crontab [ -u user ] [ -i ] { -e | -l | -r }
                (default operation is replace, per 1003.2)
        -e      (edit user's crontab)
        -l      (list user's crontab)
        -r      (delete user's crontab)
        -i      (prompt before deleting user's crontab)

Is there a way we could attempt writing over stdin, notice the
failure, then retry with the '-' option?

We do not use -e to edit, we run `crontab` and provide the contents to
stdin. `crontab -e` just opens the crontab in the users editor, which
would work with busybox as well, but that's not what's being done here.

Thank you. Of course. Muscle memory from testing crontab manually.

Thanks,
-Stolee