[arch-releng] Get Mac Address for profiles - Proof of Concept

[Dieter Plaetinck]

On Fri, 3 Apr 2009 00:01:20 +1000
Jud <jud at judfilm.net> wrote:

> On Wed, 1 Apr 2009 20:48:33 +0200
> Dieter Plaetinck <dieter at plaetinck.be> wrote:
> 
> > On Thu, 2 Apr 2009 00:06:46 +1000
> > Jud <jud at judfilm.net> wrote:
> > 
> > > Just to get the ball rolling. This script would be started by the
> > > boot process outside of aif. Any ideas/comments welcome.
> > > 
> > > #!/bin/sh
> > > # Proof of Concept
> > bash (same as other mail)
> > > 
> > > # ToDo:
> > > # Work backwards - test for wireless then wired
> > > eth2/eth1/wlan1/wlan0/eth0 any others? # Make into function(s)?
> > > # More Sanity Tests?
> > > # Another layer - groups of mac address for a profile type -
> > > profile:desktop01:<mac>,<mac>,<mac>
> > > # How would the boot process call this script without interrupting
> > > the possibility of a normal install?
> > > 
> > > # Get the MAC address for eth0
> > > var=$(ifconfig -a | grep eth0)
> > > 
> > > # We only need the MAC Address
> > > var=$(echo ${var: -19})
> > cool. i never did such a -19 thing. how does this work?
> 
> Substring Extraction
> 9.2 in the Advanced Bash Scripting Guide
> 
> The command says keep the 19 characters from the right of the string.
> 
> I do have a problem with the string, it contains a space or tab at the
> end. echo in the above command seems to remove it but without the echo
> it remains and I need to add another line: var=${var// /}. No problem,
> but was curious to know if there is a better way.
> 

Try this:
var=$(ifconfig -a | awk '/^eth0/ {print $5}')

> > you can do just var=${var: -19} btw
> > > 
> > > # Convert to be a filename for our purposes; Strip out ':'
> > > var=$(echo ${var//:/})
> > > 
> > > # Make sure it is Hex aka within the MAC Address specs and
> > > ifconfig output
> > > if [[ $var =~ [[:xdigit:]] ]]; then
> > >   echo "$var".profile
> > > else
> > >   echo "error"; exit 1
> > > fi
> > > 
> > > # Check if file exists and is readable
> > > if [ -r "$var.profile" ]; then
> > > 
> > > # Start Auto Install, when finished reboot
> > > # Note: for auto-reboot the install drive should not be the
> > > primary boot device 
> > > aif -p automatic -c $var.profile && reboot
> > > 
> > > # End of File
> > 
> > Looking good! keep it up.
> > Dieter
> 
> ok thanks, more to follow...