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Notices

By sysconfig at 2006-11-06 02:14
To get the list of username with its user ID in formatted way:

Quote:
# awk -F":" '{ print "username: " $1 "\t\tuid:" $3 }' /etc/passwd
Find the particular string from the list of files in current directory:

Quote:
# cd /etc
# for i in $(find -type f); do grep -iH nfsnobody $i; done
Or

Quote:
# grep -iH nfsnobody *
Get the no of occurrences of particular word in file:

Quote:
# awk '/ServerName/ {i=i+1} END {print i}' /etc/httpd/conf/httpd.conf
# grep ServerName /etc/httpd/conf/httpd.conf
To delete resources of semaphore arrays from memory:

Quote:
# ipcs -s | grep apache | perl -e 'while (<STDIN>) { @a=split(/\s+/); print`ipcrm sem $a[1]`}'
To check whether perl module is installed correctly or not:

If all is correct then output of this command nothing

Quote:
# perl -e 'require Mail::SPF::Query'
To install CPAN module:
Quote:
#cpan
cpan> install Mail::SPF::Query
CPAN: Storable loaded ok
Going to read /root/.cpan/Metadata
Database was generated on Thu, 24 Nov 2005 14:54:20 GMT
Mail::SPF::Query is up to date.

To get the list of IP addresses in the server:

Quote:
#ifconfig | grep -vw inet6 | grep -w inet | cut -d : -f 2 | cut -d \ -f 1
Find list of IP address along with eth device and network mask:

Quote:
# ifconfig | cut -d " " -f1,12,16 | grep -A 1 eth | tr -d - | tr -s "\n" |sed -e :a -e N -e 's/\n/ /'
Know the performance of your HardDisk:

change the device address as per your servers configuration

Quote:
# hdparm -Tt /dev/sda
Get the customized output of raw accesslog of httpd:
Navigate the folder where your http access log reside

Quote:
# tail -f access_log | awk '{if ($11 ~"\"-\"") print $1, $7, $12; else print $1, $10, $11, $12}'
The details of the present http connections can be found by using:

Quote:
# netstat -plan | grep ":80 " | awk {'print $5'} |awk -F: {'print $1'}|sort
# cat /proc/net/ip_conntrack | grep "port=80" | wc -l
Number of connection from perticular IP addfess:

Quote:
# netstat -ntu | awk '{print $5}'| cut -d: -f1 | sort | uniq -c | sort -nr | more
No of conections:

Quote:
# netstat -alntp

#/sbin/ldconfig /usr/local/lib - Update the system linker cache
Port scanning using nmap:
You can customized it to get more informative output

Quote:
# nmap -sS localhost -
instead host localhost, it could be IP address of another server which is in question

You can execute bash command a certain number of times by using something similar to the following:

Quote:
n=0;while test -$n -gt -10; do echo n=$n; n=$[$n+1]; done

That code will print "n=0", "n=1", and so on 10 times.
Only get the listing of directories:

Quote:
ls -F $1 | grep \/ | sed -e 's/\/$/4/g'
Real Time Network Activity Examples:
Quote:
root# watch -d "netstat -nalp |grep -v DGRAM |grep -v STREAM |grep -v LISTEN"
root# watch "netstat -nalp"|grep ":TCP PORT Number"
root# watch "netstat -nalp"|grep ":22"

by unSpawn on Sun, 2007-02-18 20:46
Thanks for taking the to write this down. With all due respect but IMHO this looks more like an addition to the Tricks and hints thread because it explains nothing. It isn't very consistent in what it tries to say and it's in the wrong section (Security).

by arisnb on Wed, 2009-05-13 06:11
Just add command :
1. For check ssh failure log ( in GNU/Linux Debian)
Code:
#/bin/cat /var/log/auth.log  |grep sshd:auth |grep failure |awk '{print $1"-" $2 "-" $3 "-->" $12 "->" $14 "->" $15}'
2. Kill program one time click base keyword
Code:
#for a in $( ps aux | grep  "some-thing-text" | awk '{ print $2 }'); do kill $a; done;
exp ( klill crontab )

Code:
#for a in $( ps aux | grep  "/USR/SBIN/CRON" | awk '{ print $2 }'); do kill $a; done;
3. Check cpu info
Code:
# cat /proc/cpuinfo


  



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