ping myself w/o knowing my own address

bullfrog1870 · 12-01-2006, 05:55 PM

I've been presented with a challenge to:
ping myself (eth0)
ping a peer
ping a gateway

Each to be done with a single command and no previous knowledge of the network. I say it can't be done.

Did I win the bet?

FC5

dxqcanada · 12-01-2006, 06:52 PM

Hmm,

you can ping yourself by

Code:

# ping -c1 `hostname`

then you could cheat and ping the entire network

Code:

# ping -c1 -b ` ifconfig | grep Bcast | cut -d : -f 3 | awk '{print $1}' `

or ping the default gateway

Code:

ping -c1 ` netstat -r | awk '/^default/ {print $2}' `

dxqcanada · 12-01-2006, 07:13 PM

Sooo, you may have lost the bet.

What did I win ??

bullfrog1870 · 12-02-2006, 11:55 AM

QUOTE=dxqcanada]Sooo, you may have lost the bet.

What did I win ??[/QUOTE]

How do I get my hostname from the commandline and pair it up with the ping command?

dxqcanada · 12-02-2006, 11:58 AM

Code:

# ping -c1 `hostname`

The hostname command outputs the configured hostname for your workstation ... and the ping command uses that as an argument.
Note that the command is enclosed with the "`" character.

bullfrog1870 · 12-02-2006, 12:02 PM

Quote:

Originally Posted by bullfrog1870

QUOTE=dxqcanada]Sooo, you may have lost the bet.

What did I win ??

How do I get my hostname from the commandline and pair it up with the ping command?[/QUOTE]

NEVER MIND!

I misunderstood when you put the single quotes around the hostname. I'm guessing that items inside the single quotes gets interpreted as a command.

Thanks so much - I guess I'll have to share lunch now.

dxqcanada · 12-02-2006, 12:07 PM

Not a singlequote ... it is a backquote.
Makes a big difference as it is used for command substitution.

same as the new syntax of using $( ... )

Code:

# ping -c1 $(hostname)