I have a shell script and want to assign a value to a variable. The value is the line exctrated from a file using the line number. The line number it is not fix, and could change any time.
I have tried sed, awk, head .. See my script
# Get randome line number from the file
#selectedline = `awk... (1 Reply)
Hello,
I am having trouble extracting a specific line from a file when the line number is known. My first attempt involved grep -n 'hi' (the word 'hi will always be there) to get the line number before the line that I actually want (line 4).
Extra Notes:
-I am working in a bash script.
-The... (7 Replies)
This is the line that I am using:
sed 's/^*\({3}*$\)/\1 /' <test.txt >results.txt
and suppose that test.txt contains the following lines:
http://www.example.com/200904/AUS.txt
http://www.example.com/200903/_RUS.txt
http://www.example.com/200902/.FRA.txt
What I expected to see in results.txt... (6 Replies)
FOLKS ,
i have a text file that is generated automatically of an another korn shell script, i want to bring in the fifth line of the text file in to my korn shell script and look for a particular word in the line . Can you all share some thoughts on this one.
thanks...
Venu (3 Replies)
Dear all,
I am trying to extract a number from a line in one file (task 1), duplicate another file (task 2) and replace all instances of the strings 300, in duplicated with the extracted number (task 3). Here is what I have tried so far:
for ((k=1;k<4;k++)); do
temp=`sed -n "${k}p"... (2 Replies)
I have a LOG file which looks like this
Import started at: Mon Jul 23 02:13:01 EDT 2012
Initialization completed in 2.146 seconds.
--------------------------------------------------------------------------------
--
Import summary for Import item: PolicyInformation... (8 Replies)
Hi guys,
I have been trying to do this, but... no luck so maybe you can help me.
I have a line like this:
Total Handled, Received, on queue Input Mgs: 140 / 14 => 0
I need to, get the number after the / until the =, to get only 14 .
Any help is greatly appreciated.
Thanks, (4 Replies)
In the below perl code I am using tags within each line to extract certain information. The tags that are used are:
STB >0.8 is STRAND BIAS otherwise GOOD
FDP is the second number
GO towards the end of the line is read into an array and the value returned is outputed, in the first line that... (1 Reply)
Discussion started by: cmccabe
1 Replies
LEARN ABOUT NETBSD
carp
CARP(4) BSD Kernel Interfaces Manual CARP(4)NAME
carp -- Common Address Redundancy Protocol
SYNOPSIS
pseudo-device carp [count]
DESCRIPTION
The carp interface is a pseudo-device which implements and controls the CARP protocol. carp allows multiple hosts on the same local network
to share a set of IP addresses. Its primary purpose is to ensure that these addresses are always available, but in some configurations carp
can also provide load balancing functionality.
A carp interface can be created at runtime using the ifconfig carpN create command.
To use carp, the administrator needs to configure at minimum a common virtual host ID and virtual host IP address on each machine which is to
take part in the virtual group. Additional parameters can also be set on a per-interface basis: advbase and advskew, which are used to con-
trol how frequently the host sends advertisements when it is the master for a virtual host, and pass which is used to authenticate carp
advertisements. Finally carpdev is used to specify which interface the carp device attaches to. If unspecified, the kernel attempts to set
carpdev by looking for another interface with the same subnet. These configurations can be done using ifconfig(8), or through the SIOCSVH
ioctl.
Additionally, there are a number of global parameters which can be set using sysctl(8):
net.inet.carp.allow Accept incoming carp packets. Enabled by default.
net.inet.carp.preempt Allow virtual hosts to preempt each other. It is also used to failover carp interfaces as a group. When the
option is enabled and one of the carp enabled physical interfaces goes down, advskew is changed to 240 on all
carp interfaces. See also the first example. Disabled by default.
net.inet.carp.log Log bad carp packets. Disabled by default.
net.inet.carp.arpbalance Balance local traffic using ARP. Disabled by default.
EXAMPLES
For firewalls and routers with multiple interfaces, it is desirable to failover all of the carp interfaces together, when one of the physical
interfaces goes down. This is achieved by the preempt option. Enable it on both host A and B:
# sysctl -w net.inet.carp.preempt=1
Assume that host A is the preferred master and 192.168.1.x/24 is configured on one physical interface and 192.168.2.y/24 on another. This is
the setup for host A:
# ifconfig carp0 create
# ifconfig carp0 vhid 1 pass mekmitasdigoat 192.168.1.1
netmask 255.255.255.0
# ifconfig carp1 create
# ifconfig carp1 vhid 2 pass mekmitasdigoat 192.168.2.1/24
netmask 255.255.255.0
The setup for host B is identical, but it has a higher advskew:
# ifconfig carp0 create
# ifconfig carp0 vhid 1 advskew 100 pass mekmitasdigoat
192.168.1.1 netmask 255.255.255.0
# ifconfig carp1 create
# ifconfig carp1 vhid 2 advskew 100 pass mekmitasdigoat
192.168.2.1 netmask 255.255.255.0
Because of the preempt option, when one of the physical interfaces of host A fails, advskew is adjusted to 240 on all its carp interfaces.
This will cause host B to preempt on both interfaces instead of just the failed one.
In order to set up an ARP balanced virtual host, it is necessary to configure one virtual host for each physical host which would respond to
ARP requests and thus handle the traffic. In the following example, two virtual hosts are configured on two hosts to provide balancing and
failover for the IP address 192.168.1.10.
First the carp interfaces on Host A are configured. The advskew of 100 on the second virtual host means that its advertisements will be sent
out slightly less frequently.
# ifconfig carp0 create
# ifconfig carp0 vhid 1 pass mekmitasdigoat 192.168.1.10
netmask 255.255.255.0
# ifconfig carp1 create
# ifconfig carp1 vhid 2 advskew 100 pass mekmitasdigoat
192.168.1.10 netmask 255.255.255.0
The configuration for host B is identical, except the skew is on virtual host 1 rather than virtual host 2.
# ifconfig carp0 create
# ifconfig carp0 vhid 1 advskew 100 pass mekmitasdigoat
192.168.1.10 netmask 255.255.255.0
# ifconfig carp1 create
# ifconfig carp1 vhid 2 pass mekmitasdigoat 192.168.1.10
netmask 255.255.255.0
Finally, the ARP balancing feature must be enabled on both hosts:
# sysctl -w net.inet.carp.arpbalance=1
When the hosts receive an ARP request for 192.168.1.10, the source IP address of the request is used to compute which virtual host should
answer the request. The host which is master of the selected virtual host will reply to the request, the other(s) will ignore it.
This way, locally connected systems will receive different ARP replies and subsequent IP traffic will be balanced among the hosts. If one of
the hosts fails, the other will take over the virtual MAC address, and begin answering ARP requests on its behalf.
Note: ARP balancing only works on the local network segment. It cannot balance traffic that crosses a router, because the router itself will
always be balanced to the same virtual host.
SEE ALSO netstat(1), sysctl(3), arp(4), arp(8), ifconfig(8), sysctl(8)HISTORY
The carp device first appeared in OpenBSD 3.5.
BSD October 16, 2003 BSD