amit

!/bin/bash ADMIN_EMAIL="email" PID=$$ POLL_INTERVAL=2 trap traphup HUP sleep 1 i=1 laststate="STARTUP" notify() { #echo "Service State Changed to $1" | mail -s "Service Status Notification" $ADMIN_EMAIL echo "Admin has been notified $1" } while [ $i

You can pass port as parameter too. (/usr/sbin/sshd -t : to check for syntax errors) sed -ie 's/Port.*[0-9]$/Port '2222'/gI' /etc/ssh/sshd_config

This is great script to run commands on multiple servers at once, especially if you have setup password less connections. !/bin/bash servers="srv1.example.com srv2.example.com srv3.example.com" SSH_PORT=22 cmd=$1 if [ "$cmd" == "" ]; then echo "Usage sh

C++ compiler cannot create executables :  Install gcc, gcc-c++

Displays top cpu eaters ps -eo pcpu,pid,user,args | sort -k 1 -r | head -10 Top Memory Eaters: ps -auxf | sort -nr -k 4 | head -10 Load Average : uptime | awk '{print $10}' | sed 's/,//g' Total No. of Cpus [cores]: cat /proc/cpuinfo | grep processor

This is an error with amavisd . Check the proper hostname, that could be guilty.. vi /etc/amavisd.conf and check for hostname Or, vi /etc/postfix/main.cf find content_filter and comment that out ( Temp solution ) Amavis dead but subsys locked : rm /var/amavis/amavisd.pid rm /var/amavis/

Setting up Postfix to use a remote mailserver Edit /etc/postfix/main.cf and add the following > Set this to your email provider’s smtp server. relayhost = yourisp.smtp.servername:25 #or your smtp port if different smtpd_sasl_auth_enable = yes smtpd_sasl_path = smtpd smtp_sasl_password_

Rsync : 873

Delete existing rules: iptables -F or iptables --flush Set Default Chain Policies: iptables -P INPUT DROP iptables -P FORWARD DROP iptables -P OUTPUT DROP Block an IP Address: iptables -A INPUT -s a.b.c.d -j DROP iptables -A input -i eth0 -p tcp -s <ip_addr>

Using Awk to sum the list of output: ps aux | awk '{sum +=$4}; END {print sum}' Print Line that match a pattern: awk ‘/string1/ > /string2/’  filename Print specific fields : awk ‘{print $1,$3,$5,$NF;}’ /etc/passwd [ $NF means the last field ] Initialization and Finalization: BEGIN {actions}

Note : Default packet size sniffed is 96 bytes, you can override that with -s , you can use –s 0  for complete size capture. Example usage : tcpdump -w capture.pcap -i eth0 tcp port 22 To capture or view for multiple ports : tcpdump -w capture.pcap -i eth0 tcp port 22

Define the colors : ESC_SEQ=”\x1b[” COL_RESET=$ESC_SEQ”39;49;00m” COL_RED=$ESC_SEQ”31;01m” COL_GREEN=$ESC_SEQ”32;01m” COL_YELLOW=$ESC_SEQ”33;01m” COL_BLUE=$ESC_SEQ”34;01m” COL_MAGENTA=$ESC_SEQ”35;01m” COL_CYAN=$ESC_SEQ”36;01m” echo

Reading user input with timeout: > read -t eg. > echo -n “Are you Sure ? ” if read -t 5 response; then echo ” Timed out, you didn’t make a selection” else echo “Ok proceeding” fi ** Read with prompt :** read -p “Enter Name: ” name Get File Name from full path: filename=

LIBS=”-lpthread -ldl”

The following script will calculate the Total Memory Usage by A process in Megabytes and the number of threads. You have to supply the string that will identify the process in ps aux output. sample usage  calc_memory.sh  apache > !/bin/bash STRING=$1 if [ -z "$STRING"

Pipe any output to : > awk ‘{total = total +$1}END{print total}’

Creating an activity timeout using php: > function check_session() { if (isset($_SESSION[‘last_active’]) && (time() – $_SESSION[‘last_active’] > 300)) { // last request was more than 30 minates ago /*                                    destroyPortalSession(); redirect(‘/’); session_destroy();                        // destroy session data in storage session_unset();                         // unset $_SESSION variable for the runtime */ header(“Location:

Installing Additional Yum Repositories Installing Centos Testing Repo : > rpm –import http://dev.centos.org/centos/RPM-GPG-KEY-CentOS-testing wget -O /etc/yum.repos.d/CentOS-Testing.repo http://dev.centos.org/centos/5/CentOS-Testing.repo Installing Rpm Forge Repo: Centos 6: i686 : > http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.2-2.el6.

View Mysql Process list with full query : show full processlist \G Disable Binary Logging SET sql_log_bin = 0;

CSS 2 : Image List : > ul { list-style-image: url(‘img.ext’); } Cross Browser Solution ( Clear First ) : > ul { list-style-type: none; padding: 0px; margin: 0px; } li { background-image: url(sqpurple.gif); background-repeat: no-repeat; background-position: 0px 5px; padding-left: 14px; } Set Static Content ( Doesnot moved when scrolled ) > p.pos_fixed { position:fixed; top:30px;

With increasing data, mysql tables can get defragmented and it is a good idea to optimize tables every once in a while.Getting the list of all tables that need optimization :> mysql -p -e “select concat(TABLE_SCHEMA,’.’,TABLE_NAME),Data_free from information_schema.TABLES where TABLE_SCHEMA

Follow the following steps to reset the postfixadmin password: 1. Get the Encrypted Version of the string that you want to set as password : > dovecot -s MD5-CRYPT -p | sed ‘s/{MD5-CRYPT}//’ 2. Copy the output 3. Login to Mysql database 4. Use database Vmail or whatever in your case.

In Linux, the shared libraries are usually search at /usr/lib, if you need to force it to search in a new directory then you have to create a file  with .conf extension inside /etc/ld.so.conf.d  and add the path to that file example : > vi /etc/

Search for a pattern in current directory: grep -w : match exact word grep -i : ignore case grep -v : Dont mach this grep -l : Only show filename that matches the pattern grep -n : Show the line number where the match is found. eg: grep ‘[A-Z]’ files : Lines containing a caps grep

Find Service tag for dell machines dmidecode | grep –color -i serial or dmidecode -t 1