[Tutor] Python and boot sequences

[Dave Wilder]

The switch is in a state where user process can be run once the boot sequence has been halted (the aforementioned <ESC><SHIFT><9>).
However the time between when the reboot is kicked off and when the asterisks appear (and the boot must be stopped), there is no shell
Environment.

I may be trying to hammer a nail in with a wrench.  So I'm going to do a little more digging into the switch code and get to a point where 
a shell script can be run as Alan suggested.  Then I'll be back.

Thanks all for the replies.

Dave


-----Original Message-----
From: tutor-bounces+d.wilder=f5.com at python.org [mailto:tutor-bounces+d.wilder=f5.com at python.org] On Behalf Of Alan Gauld
Sent: Wednesday, July 04, 2012 1:07 PM
To: tutor at python.org
Subject: Re: [Tutor] Python and boot sequences

On 28/06/12 13:54, Dave Wilder wrote:

> Can a Python script be written that has the ability to stop a Linux 
> device in the middle of a boot when a certain sequence occurs and then 
> perform an action?

It depends...

> For example, when I boot my switch (w/ Linux OS 2.7.3), I want to stop 
> the boot when I see a series of asterisks.  When I see this, I need to 
> hit the <ESC><SHIFT><9>

Could you do it with a bash script? If so you could do it with Python.
But I've no idea whether your switch will be in a state to run user processes at that point in its boot sequence. If you don't have a shell environment its going to be a whole lot harder.

> doing a PXE boot,

???

--
Alan G
Author of the Learn to Program web site
http://www.alan-g.me.uk/



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