Works on any machine with nmap installed. Previous version does not work on machines without "seq". Also works on subnets of any size. Show Sample Output

pings a server once per second, and beeps when the server is unreachable. Basically the opposite of: ping -a server-or-ip.com which would beep when a server IS reachable. You could also substitute beep with any command, which makes this a powerful alternative to ping -a: while true; do [ "$(ping -c1W1w1 server-or-ip.com 2>/dev/null | awk '/received/ {print $4}')" = 1 ] && date || echo 'server is down!'; sleep 1; done which would output the date and time every sec until the ping failed, in which case it would echo. Notes: Requires beep package. May need to run as root (beep uses the system speaker) Tested on Ubuntu which doesn't have beep out of the box... sudo apt-get install beep

Usefull for when you don't have nmap and need to find a missing host. Pings all addresses from 10.1.1.1 to 10.1.1.254, modify for your subnet. Timeout set to 1 sec for speed, if running over a slow connection you should raise that to avoid missing replies. This will clean up the junk, leaving just the IP address: for i in {1..254}; do ping -c 1 -W 1 10.1.1.$i | grep 'from' | cut -d' ' -f 4 | tr -d ':'; done Show Sample Output

This command uses ping to get the routers' IP addresses to the destination host as traceroute does. If you know what I mean..

PING parameters c 1 limits to 1 pinging attempt q makes the command quiet (or silent mode) /dev/null 2>&1 is to remove the display && echo ONLINE is executed if previous command is successful (return value 0) || echo OFFLINE is executed otherwise (return value of 1 if unreachable or 2 if you're offline yourself). I personally use this command as an alias with a predefined machine name but there are at least 2 improvements that may be done. Asking for the machine name or IP Escaping the output so that it displays ONLINE in green and OFFLINE in red (for instance).

Joker wants an email if the Brand X server is down. Set a cron job for every 5 mins with this line and he gets an email when/if a ping takes longer than 3 seconds. Show Sample Output

When run on a mac, this command will bring up a dialog box in the Terminal when server HOSTNAME first responds to a ping.

It really disables all ICMP responses not only the ping one. If you want to enable it you can use: sudo -s "echo 0 > /proc/sys/net/ipv4/icmp_echo_ignore_all"

Audio acknowledgement for host availability. When running the command from a Linux systems, you can use "festival" or "espeak" instead of "say".

Ping sweep without NMAP

Waits for all pings to complete and returns ip with mac address

After this, just type: beepwhenup You need to install "beep" before this would make the beep sound. Save it in your .profile if you want to use it later WARNING: this command won't exit until it is successful. You won't be able to CONTROL+C out of it.

Alternative to the ping check if your firewall blocks ping. Uses curl to get the landing page silently, or fail with an error code. You can probably do this with wget as well. Show Sample Output

For some reason the 2&>1 does not work for me, but the shorter stdout/stderr redirection >& works perfectly (Ubuntu 10.04).

Cleaner with a mailto assignment in crontab (if the command fails you get an email): MAILTO=admin@example.com 10,30,50 * * * * ping -q -c1 -w3 192.168.0.14 >/dev/null

Nasty perl one-liner that provides a sparkline of ping times. If you want a different history than the last 30, just put that value in. It (ab)uses unicode to draw the bars, inspired by https://github.com/joemiller/spark-ping . It's not the most bug-free piece of code, but what it lacks in robustness it makes up for in capability. :) If anyone has any ideas on how to make it more compact or better, I'd love to hear them. I included a ping to google in the command just as an example (and burned up 10 chars doing it!). You should use it with: $ ping example.com | $SPARKLINE_PING_COMMAND Show Sample Output

Will report back IP address's of all hosts that are UP. Show Sample Output

This allows for sleeping in between pings. Also, espeak needs to be installed.

This command only check the network connection from given eth. This is very useful if you are using more then one interface in your server or laptop. Show Sample Output

This is like ping -a, but it does the opposite. It alerts you if the network is down, not up. Note that the beep will be from the speaker on the server, not from your terminal. Once a second, this script checks if the Internet is accessible and beeps if it is not. I define the Net as being "UP", if I can ping Google's public DNS server (8.8.8.8), but of course you could pick a different static IP address. I redirect the beep to /dev/console so that I can run this in the background from /etc/rc.local. Of course, doing that requires that the script is run by a UID or GID that has write permissions to /dev/console (usually only root). Question: I am not sure if the -W1 flag works under BSD. I have only tested this under GNU/Linux using ping from iputils. If anybody knows how portable -W is, please post a comment.

I have used single packet, and in a silent mode with no display of ping stats. This is with color and UI improvement to the http://www.commandlinefu.com/commands/view/10220/check-if-a-machine-is-online. It is as per the enhancements suggested. Show Sample Output

Online games have pretty good lag compensation nowadays, Sometimes though, you really want to get some warning about your latency, e.g. while playing Diablo III in Hardcore mode, so you know when to carefully quit the game b/c your flatmate started downloading all his torrents at once. This is done on Darwin. On Linux/*nix you would need to find another suitable command instead of `say` to spell out your latency. And I used fping because it's a little bit easier to get the latency value needed. Something similar with our regular ping command could look like this: while :; do a=$(ping -c1 google.com | grep -o 'time.*' | cut -d\= -f2 | cut -d\ -f1 | cut -b1-4); [[ $a > 40 ]] && say "ping is $a"; sleep 3; done