CentOS - May 2019 - how to find out the number of updates for a system

Once upon a time, mark <m.roth at 5-cent.us> said:
> Ralf Prengel wrote:
> > Hallo,
> > I need the information how many updates are available for a system.
> > What is the best way to find it out in a one line bash script.
> >
> yum check-update, perhaps?
Note that "yum check-update" or "yum list updates" won't
tell you how
many packages would be installed with "yum update"... dependencies and
such are not resolved for check-update/list updates.

-- 
Chris Adams <linux at cmadams.net>

On Wed, May 22, 2019 at 7:49 AM Chris Adams <linux at cmadams.net> wrote:
> Once upon a time, mark <m.roth at 5-cent.us> said:
> > Ralf Prengel wrote:
> > > Hallo,
> > > I need the information how many updates are available for a
system.
> > > What is the best way to find it out in a one line bash script.
> > >
> > yum check-update, perhaps?
>
> Note that "yum check-update" or "yum list updates"
won't tell you how
> many packages would be installed with "yum update"...
dependencies and
> such are not resolved for check-update/list updates.


otoh, its pretty rare that an update has a new dependency...    if the
package is installed, its existing dependencies are also installed, and if
they have updates, check-update would show them all, would it not?



-- 
-john r pierce
  recycling used bits in santa cruz

Once upon a time, John Pierce <jhn.pierce at gmail.com>
said:
> otoh, its pretty rare that an update has a new dependency...    if the
> package is installed, its existing dependencies are also installed, and if
> they have updates, check-update would show them all, would it not?
It's not as rare as you might think, especially at point-release time.
There are often new dependencies when packages get updates beyond just
bug patching, sometimes an installed package might get obsoleted by a
different package (can't remember if that shows up in check-update),
etc.

-- 
Chris Adams <linux at cmadams.net>

Chris Adams wrote:
> Once upon a time, mark <m.roth at 5-cent.us> said:
>
>> Ralf Prengel wrote:
>>
>>> Hallo,
>>> I need the information how many updates are available for a system.
>>> What is the best way to find it out in a one line bash script.
>>>
>>>
>> yum check-update, perhaps?
>
> Note that "yum check-update" or "yum list updates"
won't tell you how
> many packages would be installed with "yum update"...
dependencies and such
> are not resolved for check-update/list updates.
>
Ok, you want it all, fine:
echo "n" | yum  update | egrep "Install|Upgrade"

      mark