cron job question (for checking kernel updates)

[inode0]

On Wed, Oct 2, 2013 at 10:42 PM, Ranjan Maitra
<maitra.mbox.ignored at inbox.com> wrote:
> On Wed, 2 Oct 2013 20:53:52 -0500 inode0 <inode0 at gmail.com> wrote:
>
>> On Wed, Oct 2, 2013 at 10:10 AM, Ranjan Maitra
>> <maitra.mbox.ignored at inbox.com> wrote:
>> > Hi,
>> >
>> > I have a cron job running which yum updates all my machines once a day.
>> > All of these work fine.
>> >
>> > I also have a cron job which checks for kernel updates every hour and
>> > sends me a message if an updated kernel has been installed. Here is the
>> > relevant script:
>> >
>> > --- begin file called check-kernel.sh in my scripts/yum directory---
>> >
>> > #!/bin/bash
>>
>> export DISPLAY=:0
>
> I was wondering -- why, instead of this, the following would not work:
>
> export $(env | grep DISPLAY)

DISPLAY is not set in the environment used by cron. That was the whole
problem to begin with.

John