IFACE অপশন
The following "command" options are available for every family and
method. Each of these options can be given multiple times in a single
stanza, in which case the commands are executed in the order in which
they appear in the stanza. (You can ensure a command never fails by
suffixing them with "|| true".)
pre-up command
Run command before bringing the interface up. If this command
fails then ifup aborts, refraining from marking the interface as
configured, prints an error message, and exits with status 0.
This behavior may change in the future.
up command
post-up command
Run command after bringing the interface up. If this command
fails then ifup aborts, refraining from marking the interface as
configured (even though it has really been configured), prints
an error message, and exits with status 0. This behavior may
change in the future.
down command
pre-down command
Run command before taking the interface down. If this command
fails then ifdown aborts, marks the interface as deconfigured
(even though it has not really been deconfigured), and exits
with status 0. This behavior may change in the future.
post-down command
Run command after taking the interface down. If this command
fails then ifdown aborts, marks the interface as deconfigured,
and exits with status 0. This behavior may change in the
future.
There exists for each of the above mentioned options a directory
/etc/network/if-<option>.d/ the scripts in which are run (with no
arguments) using run-parts(8) after the option itself has been
processed. Please note that as post-up and pre-down are aliases, no
files in the corresponding directories are processed. Please use if-
up.d and if-down.d directories instead.
All of these commands have access to the following environment
variables.
IFACE physical name of the interface being processed
LOGICAL
logical name of the interface being processed
ADDRFAM
address family of the interface
METHOD method of the interface (e.g., static)
MODE start if run from ifup, stop if run from ifdown
PHASE as per MODE, but with finer granularity, distinguishing the pre-
up, post-up, pre-down and post-down phases.
VERBOSITY
indicates whether --verbose was used; set to 1 if so, 0 if not.
PATH the command search path: /usr/local/sbin:/usr/local/bin:���
/usr/sbin:/usr/bin:/sbin:/bin
Additionally, all options given in an interface definition stanza are
exported to the environment in upper case with "IF_" prepended and with
hyphens converted to underscores and non-alphanumeric characters
discarded.
When ifupdown is being called with the --all option, before doing
anything to interfaces, if calls all the hook scripts (pre-up or down)
with IFACE set to "--all", LOGICAL set to the current value of --allow
parameter (or "auto" if it's not set), ADDRFAM="meta" and
METHOD="none". After all the interfaces have been brought up or taken
down, the appropriate scripts (up or post-down) are executed.