Find the Hostname with IPAddress

[test@srinfosoa01 logs]$ nslookup srinfosoa01
Server:         128.166.33.44
Address:        128.166.33.44#53



nslookup 208.77.188.166 
...
Non-authoritative answer:

166.188.77.208.in-addr.arpa     name = www.example.com.

delete files before n days in the folder

find * -mtime +n -exec rm {} \;

n=1 before 1 day

n=2 before 2 days

n=7 before 7 days

Vi Search and Replace Commands

Vi: Search and Replace

Change to normal mode with <ESC>.

Search (Wrapped around at end of file):

  Search STRING forward :   / STRING.

  Search STRING backward:   ? STRING.

  Repeat search:   n

  Repeat search in opposite direction:  N  (SHIFT-n)

Replace: Same as with sed, Replace OLD with NEW:

 First occurrence on current line:      :s/OLD/NEW

  

 Globally (all) on current line:        :s/OLD/NEW/g 

 Between two lines #,#:                 :#,#s/OLD/NEW/g

  

 Every occurrence in file:              :%s/OLD/NEW/g 

remove last 70 characters in each line in the file

 rev qa1_test.txt | cut -c 70- | rev > newqa1_.txt

find out top 10 largest file/directories

To find  top 10 largest file/directories

du -a /opt/middleware | sort -n -r | head -n 10

 more human readable output try:
$ du -hsx * | sort -rh | head -10

Alert for diskspace in Weblogic Environemnts

#!/bin/bash

#admin email account

ADMIN="madhuchilipi@gmail.com"

# set usage alert threshold

THRESHOLD=10

#hostname

HOSTNAME=$(hostname)

#mail client

MAIL=/usr/bin/mail

# store all disk info here

EMAIL="/l01/apps/oracle"

for line in $(df -hP | egrep '^/l01/apps/oracle' | awk '{ print $6 "_:_" $5 }')

do

part=$(echo "$line" | awk -F"_:_" '{ print $1 }')

part_usage=$(echo "$line" | awk -F"_:_" '{ print $2 }' | cut -d'%' -f1 )

if [ $part_usage -ge $THRESHOLD -a -z "$EMAIL" ];

then

EMAIL="$(date): Running out of diskspace on $HOSTNAME\n"

EMAIL="$EMAIL\n$part ($part_usage%) >= (Threshold = $THRESHOLD%)"

elif [ $part_usage -ge $THRESHOLD ];

then

EMAIL="$EMAIL\n$part ($part_usage%) >= (Threshold = $THRESHOLD%)"

fi

done 

if [ -n "$EMAIL" ];

then 

echo -e "$EMAIL" | $MAIL -s "Alert: Partition(s) almost out of diskspace on $HOSTNAME" "$ADMIN"

fi