Desired behaviour of "ifconfig -alias"

Oliver Fromme olli at
Mon Feb 12 22:05:05 UTC 2007

Brooks Davis wrote:
 > Oliver Fromme wrote:
 > > True, not often, but sometimes.  I had cases like that in
 > > certain environments with bridged networks and arp proxies.
 > > 
 > > I'm fine with your proposed syntax, as long as all the
 > > existing ifconfig possibilities continue to be possible,
 > > i.e. no regression.
 > FWIW, it's HEAD and 6.1.  We've actually got the aliases syntax labled
 > as deprecated in the manpage.

Interesting, I wasn't aware of that.  I'll update my
rc.conf where possible.

 > We might want to add a feature to set the
 > broadcast address.


 > > Yup, I agree, that's a PITA.  That could be solved in the
 > > shell code, though, by not enumerating until a number
 > > doesn't exist, but instead looking at the set of all
 > > shell variables that have been set, similar to this:
 > > 
 > > set | grep "^ifconfig_${IFACE}_alias" | cut -f1 -d= | ...
 > Unfortuanly grep in in /usr/bin so can't be used.

Well, ed is in /bin and can be used as a replacement for
grep; the syntax is just a little more awkward.

Or use the common IFS trick:

set | while read VAR VALUE; do
        case "$VAR" in

 > { while read _var; do
 >         _var=${_var%%=*}
 >         case $_var in
 >         ifconfig_${IFACE}_alias*)
 >                 <...>
 >                 ;;
 >         esac
 > done } < `set`

Yup, that would work, too, except that you have to write
"set | while read _var; do ...".  The "< `set`" will not

Best regards

Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing b. M.
Handelsregister: Registergericht Muenchen, HRA 74606, USt-Id: DE204219783
Any opinions expressed in this message are personal to the author and may
not necessarily reflect the opinions of secnetix GmbH & Co KG in any way.
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