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Re: autodetecting MBR location



On Wednesday 03 January 2001 00:24, Tollef Fog Heen wrote:
> | My lilo configuration scripts need to be able to infer the correct
> | location for the MBR.  I am currently using the following algorithm:
> | take root fs device from /etc/fstab and do the following:
> | s/[0-9]*//
> | s/part$/disc/
>
> What is the use of the first s/?  Unless your first letter is a digit,
> it will just remove the zero-width string '' between the first / and
> the beginning of the string.
>
> A better solution will probably be to
>
> s/[0-9]$//
>
> which will remove 5 from /dev/hda5.

Correct.  In my code I have s/[0-9]*$//.  That part of my email was re-typed 
from memory and I missed a character.

The discussion this generated was enlightening though.


On Wednesday 03 January 2001 01:00, Bart Schuller wrote:
> However, stylistically s/[0-9]*// is better written as s/[0-9]+//
> because the case where no digits match is better classified as
> "not a match".

Good point!  I have changed my code accordingly.

On Wednesday 03 January 2001 02:33, Tollef Fog Heen wrote:
> s/\d+// on devfs devices is dangerous, you'll get rid of the host
> number:
>
> perl -e '$_ = "/dev/ide/host0/bus0/target0/lun0/part1"; s/[0-9]+//; print
> $_,"\n"' /dev/ide/host/bus0/target0/lun0/part1

Right.  The s/[0-9]+$// should do it.


Now does anyone have suggestions about what file name I should give to my 
mini-perl program or what else I should do to make it generally usable?

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