if_up

Ensure a TCP/IP interface is available

If you are not root, specify the full path: /usr/sbin/if_up.

Syntax:

if_up [-ap] [-r retries] [-s seconds] interface...

Options:

-a

Wait until all specified interfaces are configured. The default is to wait until a single interface is configured.

-p

Wait only until the specified interfaces are present. The default is to wait until the interfaces are both present and configured. This is useful if you intend to configure the interface manually, after it is present (e.g. using the ifconfig utility).

-r retries

The number of times to walk the interface list. The default is 5.

-s seconds

Wait this number of seconds before rewalking the interface list. The default is 1.

interface

Name of the interface to wait on (e.g. en0, en1, ...).

Description:

You can use this convenience utility while booting to ensure a TCP/IP interface is available to those utilities that require one. It's primarily intended for use with the dhcp.client. When if_up is run in the foreground in a startup script, the script doesn't continue until the specified interfaces are marked as "UP" and have been assigned an IP address, or the utility has timed out.

Examples:

See dhcp.client.

Files:

libsocket.so

The if_up utility requires the libsocket.so shared library.

/usr/sbin/if_up

The if_up utility is located in the /usr/sbin/ directory, which is not included in the default PATH of non-root users. If you are not root, specify the full path.

Exit status:

0

Success.

>0

An error occurred.