vmstat reports  information about processes, memory, paging, block IO, traps, and cpu activity. The first report produced gives averages since the last reboot.   Additional  reports  give information on a sampling period of length delay. The process and memory reports are instantaneous in either case. [root@linuxArticles.org ~]# vmstat -s 4087800  total memory 1643176  used m...

An ISO image is an disk image of an optical disc using a conventional ISO format. ISO image files typically have a file extension of .ISO. The name "ISO" is taken from the ISO 9660 file system used with CD-ROM media, but an ISO image can also contain UDF file system because UDF is backward-compatible to ISO 9660. You can mount an ISO images via the loop device under Linux. To mount ISO...

Backing up MySQL database is a very important system administration task, and should generally be run automatically from cron. We will use the mysqldump utility included with mysql to dump the contents of the database to a text file that can be easily restore. # mysqldump -h localhost -u root -p root_password DataBase > DB_name_Bkp.sql This will generate a text file containing ...

Fileop utility does file operation on the filesystem and gives the ops/sec for each operation. This tool will be useful to test your filesystem performance as well as storage performance. Or, if you are going to select a filesystem or storage that is going to host huge number of small files (like source codes), then fileop can be used for benchmarking. First Install  ...

Reading or accessing NTFS partitions in Linux is important for many reasons. NTFS-3G is an open source cross-platform implementation of the Microsoft Windows NTFS file system with read-write support. NTFS-3G often uses the FUSE file system interface, so it can run unmodified on many different operating systems.  Before we start, make sure that you have rpmforge repository configured. If you do not have,...

After downloading ISO file from Fedora/CentOS, you can check the integrity of the ISO-file with a checksum, the md5sum. The mirror will offer you a separate text file to download with a 128 bit string of characters. This string has to be exactly the same as the one you get when you do: # md5sum file.iso 0c0f8ff9b6fb60a4778288de0d9e7f46  file.iso We assume that, you have downloaded ...

In computer terminology, a honeypot is a trap set to detect, deflect, or in some manner counteract attempts at unauthorized use of information systems. Generally it consists of a computer, data, or a network site that appears to be part of a network, but is actually isolated, (un)protected, and monitored, and which seems to contain information or a resource of value to attackers. STEP 1:...

Do you lost or forgot mysql root password ? No problem...! You can recover MySQL database server password with following steps. First Stop mysql service. # /etc/init.d/mysqld stop Start MySQL server without password: # mysqld_safe   - -skip-grant-tables & Connect to mysql server using mysql client: # mysql -u root Setup new MySQL root user password mysql> use mysql; mysql> update user set p...

eAccelerator is a free open-source PHP accelerator, optimizer, and dynamic content cache. It increases the performance of PHP scripts by caching them in their compiled state, so that the overhead of compiling is almost completely eliminated. It also optimizes scripts to speed up their execution. eAccelerator typically reduces server load and increases the speed of your PHP code by 1-10 times. I have tested this...

The Multi Router Traffic Grapher (MRTG) is a network or resource monitoring tool used by System Administrators across the Globe. MRTG generates HTML pages containing PNG images, which provides a real time visual representation of network traffic and system resources. STEP 1: Install MRTG with required packages # yum install mrtg net-snmp net-snmp-utils -y STEP 2:...

Do you want to create a document using windows fonts in Linux? No problem, please install windows fonts using one of mentioned method. Method 1: Copy the *.ttf (True Type Fonts) fonts like Arial, Tahoma, Verdana, Courier New and Times New Roman from the windows partition to the fonts:// location in nautilus. Method 2: For Ubuntu users, and since Ubuntu does not have a...

“ViCompress HTTP proxy server reduces download time by gzip compressing text pages before sending them on the client. This results in faster download times, especially over slow network connections. ViCompress works with existing web servers and web browsers. All modern browsers (Internet Explorer, Firefox, Safari, Chrome) recognize gzip-encoded data, and will automatically decompress the data on the f...

memtester is a user-space utility for testing the memory subsystem in a computer to determine if it is faulty. It does a good job of finding intermittent faults and non-deterministic faults. It has many tests to help catch borderline memory. memtester should compile and run on any 32- or 64-bit Unix or Unix-like system. Download latest version of memtester from...

Swap space in Linux is used when the amount of physical memory (RAM) is full. If the system needs more memory resources and the RAM is full, inactive pages in memory are moved to the swap space. While swap space can help machines with a small amount of RAM, it should not be considered a replacement for more RAM. Swap space is located on hard drives, which have a slower access time than physical...

In computer science, Memory Leakage occurs when a computer software or program consumes required memory but unable to memory after completing its task or when no longer needed to Operating System. There are two types of Memory Leakage. One is Virtual Memory Leakage and another is Real Memory Leakage. Now first Identify cached memory or unused memory by executing, ...

By default, when we are creating new user to Linux OS, all files from /etc/skel are copied to the new user's home directory. There are few files included in /etc/skel/ by default. * /etc/skel/.bash_logout * /etc/skel/.bashrc * /etc/skel/.profile * /etc/skel/.cshrc If you want to share some files, including rules and regulations to new users, simply add it...

By default, MySQL only allows connections from the localhost address – 127.0.0.1. The configuration file is usually found in /etc/my.cnf. To switch MySQL to listen on TCP, Open /etc/my.cnf or /etc/mysql/my.cnf. # vim /etc/my.cnf Modify line as below # bind-address  = 127.0.0.1 Save and Exit the file. Now restart the database server by executing, # /e...

We can configure apache – httpd service to listen Multiple ports via Listen directive. By default httpd listens on TCP port 80. To configure multiple ports, open file /etc/httpd/conf/httpd.conf and modify the Listen directive tells the server to accept incoming requests on the specified port # vi /etc/httpd/conf/httpd.conf Find, Listen 80 Force apache to listen to port 8...

YUM is an interactive, rpm based, package manager. It can automatically perform system updates, including dependency analysis and obsolete processing based on "repository" metadata. It can also perform installation of new packages, removal of old packages and perform queries on the installed and/or available packages among many other commands/services (see below). yum is similar to other high level package ...

If you run a dual-boot system with Linux and Windows, and reinstalling Windows XP after OS corrupt.  Windows XP will wipes over write grub entry or writing MBR sector. To recover GRUB, STEP 1: Boot off the Live CD enter into rescue mode, STEP 2: Open a Terminal and type in the following commands, noting that the first command will put you into the grub “prompt”, and ...

MAC stands for Media Access Control and in a sense the MAC address is a computer's true name on a LAN. An Ethernet MAC address is a six byte number, usually expressed as a twelve digit hexadecimal number. To change this setting, we’ll need to edit the /etc/network/interfaces file. You can choose to use a different editor if you’d like. $ sudo gedit /etc/network/interfaces You s...

Wireshark Network Analyzer is use full to track network packets. To sniff MySQL packets and decoding it, we will use mysqlsniffer. Note: This will not usually work for local connections. First, install libpcap-dev, which is the development library that allows an application to sniff network packets. $ sudo  apt-get install ...

For mysql, the system administrator user is called root. We will use the mysqladmin utility from a command line to set the new password. Default password is not secured at all. By default in RedHat, Fedora and Centos default password is null. So it is always better to set root password. To re-set root password, first stop mysql service. # service mysqld stop # mysqld_safe...

PowerDNS is a DNS server, written in C++ and licensed under the GPL. It runs on most Unix derivatives and on Microsoft Windows. PowerDNS can be managed through a web interface (PowerAdmin). Install MySQL, # yum install mysql* -y After installation, start it and create system startup links for MySQL. # service mysqld start; chkconfig mysqld on If you want to set root password, # mysqladmin -u root...

You can easily block SSH server attacks including dictionary based attacks and brute force attacks using a Python based script - DenyHosts. It analyzes the sshd log messages to determine what hosts or IPs are attempting to hack into your system. STEP 1: Enable Rpmforge Repo in your system, For 32bit CentOS / RHEL Linux enter: # rpm -Uhv...