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...

Rsync is a fast and extraordinarily versatile file copying tool. It can copy locally, to/from another host over any remote shell, or to/from a remote rsync daemon. It offers a large number of options that control every aspect of its behaviour and permit very flexible specification of the set of files to be copied. It is famous for its delta-transfer algorithm, which reduces the amount of data...

bzip2 compresses  files  using  the Burrows-Wheeler block sorting text compression algorithm, and Huffman coding.   Compression  is  generally considerably   better   than   that   achieved   by  more  conventional LZ77/LZ78-based compressors, and approaches the performance of the  PPM family of statistical compressors. To list the contents of a tar.bz2 file, use tar command as follows: ...

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...

The mysqldump client is a backup program originally written by Igor Romanenko. It can be used to dump a database or a collection of databases for backup or transfer to another SQL server (not necessarily a MySQL server). The dump typically contains SQL statements to create the table, populate it, or both. However, mysqldump can also be used to generate files in CSV, other delimited text, or XML...

Nowadays, GMail servers are very much reliable and give you a couple of GiBs for free of cost! So, it is the best place to store your linux system's important data. In order to accomplish this, first create a directory named “backup” in the root directory of your system: # cd / && mkdir backup Now, you need to create a script, which will perform backup and mail it for you...

Mozilla Firefox is a free and open source web browser descended from the Mozilla Application Suite and managed by Mozilla Corporation. As of October 2010, Firefox is the second most widely used browser, with 30% of worldwide usage share of web browsers. In Germany, Firefox is the most popular browser with 60% usage says Wikipedia. To install Firefox 4 on Fedora Linux, # vim ...

Nginx quickly delivers static content with efficient use of system resources. It can deploy dynamic HTTP content on a network using FastCGI handlers for scripts, and can serve as a very capable software load balancer. Nginx uses an asynchronous event-driven approach to handling requests which provides more predictable performance under load, in contrast to the Apache HTTP server model that uses a threaded or...

For Authentication, Account Management and Authorization, PAM is the core module and pam_unix provides mentioned functionality. Same module can be used to maintain a list of old passwords for every user. This is useful if you want to disallow use of old passwords. You can find out old password list from /etc/security/opasswd file. Open /etc/pam.d/system-auth file of Fedora Core or Red Hat or...

  This article will guide you through the necessary steps to install ipw3945 wireless adapter on a CentOS / RHEL based distribution. Before we start, make sure that you have rpmforge repository configured. If you do not have, download it from here. # wget http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.2-2.el5.rf.i386.rpm # rpm -ivh...

vm.swappiness is a tunable kernel parameter that controls how much the kernel favors swap over RAM. At the source code level, it’s also defined as the tendency to steal mapped memory. A high swappiness value means that the kernel will be more apt to unmap mapped pages. A low swappiness value means the opposite, the kernel will be less apt to unmap mapped pages. In other words, the higher the v...

There are various methods to run multiple instances of mysql (on different ports) on the same machine. Here I have used the same binary and used a separate configuration file (with separate port, pid, socket and data directory). We need to create new directories for our datadir and log folder (if used). Also we need to assign proper permissions on those folders: # mkdir /var/lib/mysql2 # chown -R mysql.mysql...

Google has recently released their very own DNS resolver with main goals of making web browsing faster and safer. Since Google's search engine already crawls the web on a daily basis and in the process resolves and caches DNS information, they wanted to make use of their technology to experiment with new ways of addressing some of the existing DNS challenges around performance and security. For advanced...

Every time I connect to Linux server, I receive the same message and I’m getting tired of seeing it, so I decided to change the message to something else. Here’s the message that I get every time: [root@server1 ~]# ssh linuxarticles.org root@linuxarticles.org's password: Last login: Mon Oct 11 18:58:43 2010 from loc...

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,...

Single-User mode is used for a system recovery. However, by default, no authentication is used if single-user mode is selected. This can be used to bypassing security on the server and gaining root access. To enable authentication for single-user mode, open the /etc/inittab, file: # vi /etc/inittab Add the following line to the...

To restricts Users from uploading File Size, we can configure Apache with LimitRequestBody Directive. You can add this directive using .htaccess file or httpd.conf file under virtual host or directory configuration options. You can set value (in bytes) from 0 (unlimited) to 2147483647 (2GB) that are allowed in a request body. For example, limit /var/www/html/linuxarticles.org/uploads to 200K,...

The default configuration for firewall is to reject all incoming packets from outside. To allow it, we need to open particular port in Firewall. The default configuration file for iptables based firewall under RHEL / CentOS / Fedora Linux is /etc/sysconfig/iptables. Open /etc/sysconfig/iptables, # vim /etc/sysconfig/iptables Append rule as follows: -A RH-Firewall-1-INPUT -m state...

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 ...

SparkleShare is a syncing and collaboration tool that shines by its absence. it's designed to get out of your way, to make sharing documents and collaboration easier, and to make peers aware of what you are doing says its project site. With SparkleShare, you are given an option to host your remote folder on your own server, Github, Gitorious, The GNOME Project. Sharing...

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:...

By default after a kernel panic, Linux kernel just waits there for a system administrator to hit the Ctrl+Alt+Del to restart or power cycle button. This is because of the value set on "kernel.panic" parameter to Linux Kernel. # cat /proc/sys/kernel/panic 0 or # sysctl -a | grep kernel.panic kernel.panic = 0 To disable this and make the Linux OS...

Do you want to Download your favorite you tube video in Linux? No problem! Here I have mentioned all steps to download you tube video using Linux Terminal.   Step 1: Install youtube-dl package by executing, On Ubuntu, $ sudo apt-get install youtube-dl On Fedora, RedHat, CentOS, # yum install youtube-dl -y Step 2: After having successfully installed youtube-dl, open a...

MySQL is a simple SQL shell (with GNU read line capabilities). It supports interactive and non interactive use. When used interactively, query results are presented in an ASCII-table format. When used non interactively (for example, as a filter), the result is presented in tab-separated format. The output format can be changed using command options. After Installation of MySQL on Linux System, start it by, #...

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...