Ping inside FOR loop Post: 302477475

10 More Discussions You Might Find Interesting

1. IP Networking

ping loop

i need to write a script that can loop through ej.192.162.0.0 to 192.162.0.256 find the ones that are connected and the ones not connected write the name , ip address and connection status of each one in a file to later use it in perl to create a web page with the information thanks guys

2. Shell Programming and Scripting

help: infinant loop script - host ping test

need to check on some hosts and send an email if there status changes I wanna put together a script in bash that will allow me to check the up/down state of a single host via ping i want it to run in a continuous loop so I can just fire the script and forget about it(dont want cron to drive...

3. Shell Programming and Scripting

variable inside variable inside loop headache

Hi Gurus I have a file called /tmp/CMDB which looks like this serial: 0623AN1208 hostname: server1 model: x4100 assetID: 1234 I am writing a for loop that will go through this file line by line creating a variable of itself. Using the first iteration of the loop (i.e. the first line) as...

4. Shell Programming and Scripting

Using variables created sequentially in a loop while still inside of the loop [bash]

I'm trying to understand if it's possible to create a set of variables that are numbered based on another variable (using eval) in a loop, and then call on it before the loop ends. As an example I've written a script called question (The fist command is to show what is the contents of the...

5. Shell Programming and Scripting

Using 'su' inside a loop

Hi, I am using su within a for loop. As you might expect, it prompts for password during each loop execution. Here is my piece of code: for i in $LIST do if then DATABASE=`echo $i | awk -F "|" '{ print $1 }'` USER_ID=`echo $i | awk -F "|" '{ print $2 }'` su - apstage -c...

6. Shell Programming and Scripting

BASH loop inside a loop question

Hi all Sorry for the basic question, but i am writing a shell script to get around a slightly flaky binary that ships with one of our servers. This particular utility randomly generates the correct information and could work first time or may work on the 12th or 100th attempt etc !....

7. Programming

Perl Ping Loop

Hi All i have an issue with ping, we are using dhcp and so if the machine has been offline and i ping it, i get " ping: unknown host <hostname> is there a way i can stick a loop somewhere so it would keep trying when it got the unknown host error and then when the machine came back online...

8. Shell Programming and Scripting

If inside If loop

Hi All, Below is the very simple code snippet but it si giving me syntax error #!/bin/bash #To ensure If JMS directory exists or not ServerName=$(hostname) #To ensure If JMS directory exists or not echo $ServerName if ; then echo "Inside First If" if ; then echo 'JMS...

9. UNIX for Dummies Questions & Answers

Write a while loop inside for loop?

I'm taking a unix class and need to countdown to 0 from whatever number the user inputs. I know how to do this with a while or until loop but using the for loop is throwing me off.... I know I can use an if-then statement in my for loop but can I include a while loop in my for loop?

10. IP Networking

Loop in /24 Subnet, No ping beyond .1 and .2

Running 3650 switch. I have this odd issue where I cannot get 4 new Centos 7 boxes pinging out on public IPs (nor pinging in), only gateway .1 and first public IP .2 This is what I see, which doesn't look normal. How do I fix this? The server itself is configured fine (Centos 7) # cat...

LEARN ABOUT CENTOS

simple

Simple action in tc(8)						       Linux						    Simple action in tc(8)

NAME

       simple - basic example action

SYNOPSIS

       tc ... action simple [ sdata STRING ] [ index INDEX ] [ CONTROL ]

       CONTROL := { reclassify | pipe | drop | continue | ok }

DESCRIPTION

       This  is  a  pedagogical example rather than an actually useful action. Upon every access, it prints the given STRING which may be of arbi-
       trary length.

OPTIONS

       sdata STRING
	      The actual string to print.

       index INDEX
	      Optional action index value.

       CONTROL
	      Indicate how tc should proceed after executing the action. For a description of the possible CONTROL values, see tc-actions(8).

EXAMPLES

       The following example makes the kernel yell "Incoming ICMP!" every time it sees an incoming ICMP on eth0. Steps are:

       1)  Add an ingress qdisc point to eth0

       2)  Start a chain on ingress of eth0 that first matches ICMP then invokes the simple action to shout.

       3)  display stats and show that no packet has been seen by the action

       4)  Send one ping packet to google (expect to receive a response back)

       5)  grep the logs to see the logged message

       6)  display stats again and observe increment by 1

	 hadi@noma1:$ tc qdisc add dev eth0 ingress
	 hadi@noma1:$tc filter add dev eth0 parent ffff: protocol ip prio 5 
	     u32 match ip protocol 1 0xff flowid 1:1 action simple sdata "Incoming ICMP"

	 hadi@noma1:$ sudo tc -s filter ls  dev eth0 parent ffff:
	  filter protocol ip pref 5 u32
	  filter protocol ip pref 5 u32 fh 800: ht divisor 1
	  filter protocol ip pref 5 u32 fh 800::800 order 2048 key ht 800 bkt 0 flowid 1:1
	    match 00010000/00ff0000 at 8
	    action order 1: Simple <Incoming ICMP>
	     index 4 ref 1 bind 1 installed 29 sec used 29 sec
	     Action statistics:
		 Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
		 backlog 0b 0p requeues 0

	 hadi@noma1$ ping -c 1 www.google.ca
	 PING www.google.ca (74.125.225.120) 56(84) bytes of data.
	 64 bytes from ord08s08-in-f24.1e100.net (74.125.225.120): icmp_req=1 ttl=53 time=31.3 ms

	 --- www.google.ca ping statistics ---
	 1 packets transmitted, 1 received, 0% packet loss, time 0ms
	 rtt min/avg/max/mdev = 31.316/31.316/31.316/0.000 ms

	 hadi@noma1$ dmesg | grep simple
	 [135354.473951] simple: Incoming ICMP_1

	 hadi@noma1$ sudo tc/tc -s filter ls  dev eth0 parent ffff:
	 filter protocol ip pref 5 u32
	 filter protocol ip pref 5 u32 fh 800: ht divisor 1
	 filter protocol ip pref 5 u32 fh 800::800 order 2048 key ht 800 bkt 0 flowid 1:1
	   match 00010000/00ff0000 at 8
	    action order 1: Simple <Incoming ICMP>
	     index 4 ref 1 bind 1 installed 206 sec used 67 sec
	    Action statistics:
	    Sent 84 bytes 1 pkt (dropped 0, overlimits 0 requeues 0)
	    backlog 0b 0p requeues 0

SEE ALSO

       tc(8) tc-actions(8)

iproute2							    12 Jan 2015 					    Simple action in tc(8)

10 More Discussions You Might Find Interesting

1. IP Networking

ping loop

Discussion started by: djbilly

2. Shell Programming and Scripting

help: infinant loop script - host ping test

Discussion started by: zeekblack

3. Shell Programming and Scripting

variable inside variable inside loop headache

Discussion started by: hcclnoodles

4. Shell Programming and Scripting

Using variables created sequentially in a loop while still inside of the loop [bash]

Discussion started by: DeCoTwc