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Full Discussion: last line from grep resullt
Top Forums Shell Programming and Scripting last line from grep resullt Post 302281370 by mjmtaiwan on Wednesday 28th of January 2009 07:53:51 PM
Old 01-28-2009
I needed to get the local IP of devices getting their addresses from DHCP by mac address.

Unfortunately, the file was long and devises had multiple IPs. Figuring that the last instance of the IP was the current IP I used cat, grep, tail, sed and cut in one line.

I am sure there is a better way to do this but at least it works.

cat /var/lib/dhcp/dhcpd.leases | grep 00:04:f2:12:05:90 -B5 | tail -6 | sed -n '1p' | cut -d' ' -f2

Hope this helps.
 

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LEARN ABOUT CENTOS

dhclient.leases

dhclient.leases(5)						File Formats Manual						dhclient.leases(5)

NAME

       dhclient.leases - DHCP client lease database

DESCRIPTION

       The Internet Systems Consortium DHCP client keeps a persistent database of leases that it has acquired that are still valid.   The database
       is a free-form ASCII file containing one valid declaration per lease.   If more than one declaration appears for a given  lease,  the  last
       one in the file is used.   The file is written as a log, so this is not an unusual occurrence.

       The format of the lease declarations is described in dhclient.conf(5).

FILES

       /var/lib/dhclient/dhclient.leases

SEE ALSO

       dhclient(8), dhcp-options(5), dhclient.conf(5), dhcpd(8), dhcpd.conf(5), RFC2132, RFC2131.

AUTHOR

       dhclient(8)  was written by Ted Lemon under a contract with Vixie Labs.	 Funding for this project was provided by Internet Systems Consor-
       tium.  Information about Internet Systems Consortium can be found at https://www.isc.org.

																dhclient.leases(5)
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