document latest command line changes:

new: -D to list interfaces
changed: -i will also accept indices (rather than complete names only)

text copied from the tethereal.pod file

svn path=/trunk/; revision=16793

1 files changed, 31 insertions, 4 deletions

diff --git a/doc/ethereal.pod b/doc/ethereal.pod
index d8463bc26d..93ade4c7b3 100644
--- a/doc/ethereal.pod
+++ b/doc/ethereal.pod
@@ -10,6 +10,7 @@ S<[ B<-a> capture autostop condition ] ...>
 S<[ B<-b> capture ring buffer option ] ...>
 S<[ B<-B> capture buffer size (Win32 only) ] >
 S<[ B<-c> capture packet count ]>
+S<[ B<-D> ]>
 S<[ B<-f> capture filter ]>
 S<[ B<-g> packet number ]>
 S<[ B<-h> ]>
@@ -220,6 +221,25 @@ disk. If you encounter packet drops while capturing, try to increase this size.
 Set the maximum number of packets to read when capturing live
 data.
 
+=item -D
+
+Print a list of the interfaces on which B<Ethereal> can capture, and
+exit.  For each network interface, a number and an
+interface name, possibly followed by a text description of the
+interface, is printed.  The interface name or the number can be supplied
+to the B<-i> flag to specify an interface on which to capture.
+
+This can be useful on systems that don't have a command to list them  
+(e.g., Windows systems, or UNIX systems lacking B<ifconfig -a>);
+the number can be useful on Windows 2000 and later systems, where the
+interface name is a somewhat complex string.
+
+Note that "can capture" means that B<Ethereal> was able to open
+that device to do a live capture; if, on your system, a program doing a
+network capture must be run from an account with special privileges (for
+example, as root), then, if B<Ethereal> is run with the B<-D> flag and
+is not run from such an account, it will not list any interfaces.
+
 =item -f
 
 Set the capture filter expression.
@@ -235,12 +255,19 @@ Print the version and options and exit.
 =item -i
 
 Set the name of the network interface or pipe to use for live packet
-capture.
+capture. 
 
 Network interface names should match one of the names listed in
-"B<tethereal -D>".  If you're using Unix, "B<netstat -i>" or "B<ifconfig
--a>" might also work to list interface names, although not all versions
-of Unix support the B<-a> flag to B<ifconfig>.
+"B<ethereal -D>" (described above); a number, as reported by
+"B<ethereal -D>", can also be used.  If you're using UNIX, "B<netstat
+-i>" or "B<ifconfig -a>" might also work to list interface names,
+although not all versions of UNIX support the B<-a> flag to B<ifconfig>.
+
+If no interface is specified, B<Ethereal> searches the list of
+interfaces, choosing the first non-loopback interface if there are any
+non-loopback interfaces, and choosing the first loopback interface if
+there are no non-loopback interfaces; if there are no interfaces,
+B<Ethereal> reports an error and doesn't start the capture.
 
 Pipe names should be either the name of a FIFO (named pipe) or ``-'' to
 read data from the standard input.  Data read from pipes must be in