How to Recover deleted files in Linux I had delete a folder from linux,but it was an important folder,so I try hard to recovered and failed,but never quit to R & D about the concept,after I found some tool, We will recover deleted file and folder with lsof,but it not recover those file and folder deleted with -r,after lot of R & D i found some tool,below are the tool for recovery. 1.Test-disk utility 2.extundelete 3.scalpel 4.autopsy and most reliable of all these is 5.Foremost we can use them with the help of google,
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Cron Job in Linux I got very confused and got lot problem while running cron job,also not found proper structure on google so decide to writ my experience,below are step wise cron job. minute: * * * * * /etc/postfix/queuegraph-rrd.sh This script run every minute */5 * * * * /bin/bash /root/mailq.sh this script run every five minute #*/57 * * * * /bin/bash /root/iptables.sh this script run on 57 minute hour. 0 * * * * run at every hour 0 23 * * * /bin/bash /root/pflogsumm.sh this script run at 11 pm day 15 15 15 * * This will run at 3:15 on every 15 days 15 15 L * * This will run on 3:15 of every last day of month 10 0 1 * * /bin/bash /root/change_always_bcc.sh this script run at 12,10 am night 1st day of month month 15 15 15 11 * This will run on November,15 at 3:15 Day of week 15 15 * * 1-6 this will run from Monday to Saturday, at 3:15
Difference between IDE and Framework before differentiate IDE and Framework lets clear other concept first. Platform A Platform is a hardware and software on which s software is develop or build For example,Windows,Mac,Linux BSD,vmware etc Library A library refers to code that provides functions that we can call from our own code to deal with common tasks. API Application programming interface,it is an interface between server and a client This term refers to the “face” of the library, SDK This is a complete kit of software development tools for a specific platform,kit include Libraries, APIs, IDE, Documentation, etc.eg android development tool kit IDE it is an application which is used to developing, compiling and debugging applications. eg Eclipse, Visual Studio, and Intel Ii Framework A collection of different libraries and api which is reusable,it is a software or a tool eg, Hibernate, Struts and Spring
TCP Sockets TCP Socket is also called virtual port,are used in tcp and udp communication,hey are called 'virtual ports' because a single physical connector can serve multiple connections. Each side of a socket connection uses its own port number, which does not change during the life of that connection. IP ADDRESS + Port No = Socket
IP Tables Firewall in Linux IP Tables is a firewall that plays an essential role in network security for most Linux systems The packet filtering mechanism provided by iptables is organized into three different kinds of structures: tables, chains and targets ========>The default table is the filter table =======>The default policy is also a target. By default, all chains have a default policy of allowing packets. ======>A target decides the fate of a packet, such as allowing or rejecting it. =========================================== IP Table configuration tool: e.g., fwbuilder, bastille and ufw =================================== Ip table main file: /etc/sysconfig/iptables ==================================================== Tables There are three tables. Filter Rules to modify the packets This is the default and perhaps the most widely used table. It is used to make decisions about whether a packet should be allowed to reach its de
AWS Guide AWS Services and lists Following are the topic which need to cover while appearing for AWS different certification.I will try to discuss every topic in detail in future,these are the AWS services as well ,AWS ec2 and AWS s3 are the mostly used services of AWS.at end of this topic i have given AWS link which need to follow for further,reference. ======>Aws compute services============= 1.AWS elastic compute cloud(ec2) 2.AWS batch 3.AWS elastic container register y(ecr) 4.aws elastic container services(ecs) 5.AWS elastic beanstalk 6.AWS lambda 7.AWS sericesless application model(sam) ====>AWS storage services=========== 1.amazon s3 2.AWS block storage(ebs) 3.amazon file storage(efs) 4.amazon glacier 5.amazon snowball 6.amazon storage gateway =====>AWS db services====== 1.amazon aurora 2.amazon dynamo db 3.amazon elastic ache 4.amazon RDS 5.amazon Redshift =========>aws networking content delivery===== 1.amazon API gateway 2.amazon cloud front 3
SSL on Post fix I have given a task to relay post fix mail with g mail. I have post fix installed and working on y local system and delivering mail to my local user test1 and test2. Following is log for mail delivery . Feb 21 15:16:06 localhost postfix/smtpd[3149]: 102C4C42F9C: client=localhost[::1] Feb 21 15:16:23 localhost postfix/cleanup[3153]: 102C4C42F9C: message-id=<20190221094606.102C4C42F9C@mail.example.com> Feb 21 15:16:23 localhost postfix/qmgr[3141]: 102C4C42F9C: from=<test1@example.com>, size=305, nrcpt=1 (queue active) Feb 21 15:16:23 localhost postfix/local[3154]: 102C4C42F9C: to=<test2@example.com>, orig_to=<test2>, relay=local, delay=24, delays=24/0.02/0/0.02, dsn=2.0.0, status=sent (delivered to maildir) Feb 21 15:16:23 localhost postfix/qmgr[3141]: 102C4C42F9C: removed Step :Now i am going to use gmail id as relay. For this first i create:tls policy file #vim /etc/postfix/t