Hack The Sec-Leading Resource Of Linux Tutorial: Shell

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<span style="color: red; font-size: large;"><i style="color: red; font-weight: bold; text-decoration: underline;">Send Email Alert When Hardware Errors
Detected</i></span></div>
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<span style="color: red; font-size: large;"><u><b><i><br /></i></b></u></span></div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: lime; font-size: medium;"><span style="line-height: 15.6px;">[root@instructor script]# yum install mcelog -y</span></span></pre>
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<span style="font-size: large;">Default Mcelog cron file is here</span><span style="color: red; font-size: large;"> /etc/cron.hourly/mcelog.cron</span></div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: lime; font-size: medium;"><span style="line-height: 15.6px;">[root@instructor script]# vi /etc/cron.hourly/mcelog.cron

#!/bin/bash

# do not run if mcelogd is running

service mcelogd status >& /dev/null

[ $? -eq 0 ] && exit 0

# is mcelog supported?

/usr/sbin/mcelog --supported >& /dev/null

if [ $? -eq 1 ]; then

exit 1;

/usr/sbin/mcelog --ignorenodev --filter >> /var/log/mcelog </span></span></pre>
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<span style="line-height: 15.6px;"><b><span style="font-family: "georgia" , "times new roman" , serif; font-size: large;"><br /></span></b></span></div>
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<span style="font-family: "georgia" , "times new roman" , serif; font-size: large;">After that paste bellow line into you
<b>hardwareerror.sh</b> file.. </span></div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: lime; font-size: medium;"><span style="line-height: 15.6px;">[root@instructor script]# touch hardwareerror.sh
</span></span></pre>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: lime; font-size: medium;"><span style="line-height: 15.6px;">[root@instructor script]# vi hardwareerror.sh

#!/bin/bash

[ $(grep -c "error" /var/log/mcelog) -gt 0 ] && echo "Hardware Error Found $(hostname) @ $(date)" |

cat /var/log/mcelog | mail -s 'H/w Error' info@hackthesec.co.in

exit 0 </span></span></pre>
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<span style="color: red;"><span style="font-family: Georgia, Times New Roman, serif; font-size: large;">and run the script through cronjob<br /></span><span style="color: red;">Note : - If your system get any hardware issue then the script will send you a mail other wise you did </span></span></div>
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<span style="color: red;"></span></div>
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<span style="color: red;">not get any email... *Only when your system detected any issue*</span></div>
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Send Email Alert When Hardware Errors Detected

Send Email Alert When Hardware Errors Detected [root@instructor script]# yum install mcelog -y Default Mcelog cron file is here /e...

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<span style="color: #990000;"><u><i>Command Line Arguments in Linux Shell Scripting</i></u></span></h1>
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Overview :</h2>
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Command line arguments (also known as positional parameters) are the arguments specified at the command prompt with a command or script to be executed. The locations at the command prompt of the arguments as well as the location of the command, or the script itself, are stored in corresponding variables. These variables are special shell variables. Below picture will help you understand them.</div>
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Let’s create a shell script with name “<b>command_line_agruments</b>.sh”, it will show the command line argruments that were supplied and count number of agruments, value of first argument and Process ID (PID) of the Script.</div>
<pre style="background: rgb(54, 54, 54); border-radius: 7px; border: 1px solid rgb(221, 221, 221); font-family: Monaco, 'Courier New', 'DejaVu Sans Mono', 'Bitstream Vera Sans Mono', monospace; font-size: 12px; font-stretch: inherit; line-height: 19px; margin-bottom: 15px; margin-top: 15px; overflow-x: auto; overflow-y: hidden; padding: 18px 20px; vertical-align: baseline; white-space: pre-wrap;"><span style="color: white;">hackthesec@localhost:~$ cat </span><span style="color: lime;">command_line_agruments.sh</span></pre>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjlsefOqjc9D-lK7l7nUbbSTnWrLT15Wj52va4WSUeKEGKptkqE48rkEeJVeDCcSUDhD4QKT7SQEd4t8qfxO_McFeoeM-XdQ9z2vIGTQ2IyVuVWS0Zc439-2Z4vGU5Zj2OAS4Egl8MwIuCt/s1600/command-line-agruments_www.hackthesec.co.in.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="128" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjlsefOqjc9D-lK7l7nUbbSTnWrLT15Wj52va4WSUeKEGKptkqE48rkEeJVeDCcSUDhD4QKT7SQEd4t8qfxO_McFeoeM-XdQ9z2vIGTQ2IyVuVWS0Zc439-2Z4vGU5Zj2OAS4Egl8MwIuCt/s640/command-line-agruments_www.hackthesec.co.in.png" width="640" /></a></div>
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Assign Executable permissions to the Script</h6>
<pre style="background: rgb(54, 54, 54); border-radius: 7px; border: 1px solid rgb(221, 221, 221); font-family: Monaco, 'Courier New', 'DejaVu Sans Mono', 'Bitstream Vera Sans Mono', monospace; font-size: 12px; font-stretch: inherit; line-height: 19px; margin-bottom: 15px; margin-top: 15px; overflow-x: auto; overflow-y: hidden; padding: 18px 20px; vertical-align: baseline; white-space: pre-wrap;"><span style="color: white;">hackthesec@localhost:~$ chmod +x </span><span style="color: lime;">command_line_agruments</span><span style="color: white;">.sh</span></pre>
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Now execute the scripts with command line argruments</h6>
<pre style="background: rgb(54, 54, 54); border-radius: 7px; border: 1px solid rgb(221, 221, 221); font-family: Monaco, 'Courier New', 'DejaVu Sans Mono', 'Bitstream Vera Sans Mono', monospace; font-size: 12px; font-stretch: inherit; line-height: 19px; margin-bottom: 15px; margin-top: 15px; overflow-x: auto; overflow-y: hidden; padding: 18px 20px; vertical-align: baseline; white-space: pre-wrap;"><span style="color: white;">hackthesec@localhost:~$ ./command_line_agruments.sh </span><span style="color: lime;">Linux AIX HPUX VMware</span><span style="color: white;">
There are 4 arguments specified at the command line.
The arguments supplied are: Linux AIX HPUX VMware
</span><span style="color: lime;">The first argument is: Linux
</span><span style="color: white;">The PID of the script is: 16316</span></pre>
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Shifting Command Line Arguments</h5>
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The shift command is used to move command line arguments one position to the left. During this move, the first argument is lost. “<b>command_line_agruments</b>.sh” script below uses the shift command:</div>
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Now Execute the Script again.</h6>
<pre style="background: rgb(54, 54, 54); border-radius: 7px; border: 1px solid rgb(221, 221, 221); font-family: Monaco, 'Courier New', 'DejaVu Sans Mono', 'Bitstream Vera Sans Mono', monospace; font-size: 12px; font-stretch: inherit; line-height: 19px; margin-bottom: 15px; margin-top: 15px; overflow-x: auto; overflow-y: hidden; padding: 18px 20px; vertical-align: baseline; white-space: pre-wrap;"><span style="color: white;">hackthesec@localhost:~$ ./</span><span style="color: lime;">command_line_agruments</span><span style="color: white;">.sh Linux AIX HPUX VMware
There are 4 arguments specified at the command line
The arguments supplied are: Linux AIX HPUX VMware
The first argument is: Linux
</span><span style="color: lime;">The Process ID of the script is: 16369
</span><span style="color: white;">The new first argument after the first shift is: AIX
</span><span style="color: lime;">The new first argument after the second shift is: HPUX
</span><span style="color: white;">hackthesec@localhost:~$</span></pre>
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Multiple shifts in a single attempt may be performed by furnishing the desired number of shifts to the shift command as an argument.<br /><br /><a href="http://www.hackthesec.co.in/" target="_blank">www.hackthesec.co.in</a><br /><a href="http://www.twitter.com/hackthesecurity">www.twitter.com/hackthesecurity</a></div>
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Command Line Arguments in Linux Shell Scripting

Command Line Arguments in Linux Shell Scripting Overview : Command line arguments (also known as positional parameters) are the a...