FAQ

tetest

2006-08-30T13:04:00.000+05:30

Import MySQL dumpfile, SQL datafile into my database

2006-08-23T17:31:00.000+05:30

Q. How can I import a MySQL dumpfile into my database? My old hosting provider gave me data.sql file. I do have access via ssh to server.A. Login to your system using ssh or putty (from Windows based system). For example:$ ssh loginname@server.hosting.com Now type following command to import sql data file:$ mysql -u username -p -h localhost data-base-name < data.sql If you have dedicated database

Apache 403 Forbidden Error and Solution

2006-08-23T17:05:00.000+05:30

Q. I have successfully configured Apache web server for my client. But why does my clients website just say "Error 403 Forbidden"? For example when client send request http://myclient.com/something/ Apache generate a 403 error. How do I troubleshoot this problem?A. Error code start 4xx is generated because of client browser request. A 403 error code means client browser (or person who is trying

Install and Test PHP on Linux system

2006-08-22T03:19:00.000+05:30

Q. How can I install and test PHP on Linux? How do I make sure it is working on my Linux system? I am using Red Hat Fedora Core Linux.A. PHP (PHP Hypertext Preprocessor) is an open-source, programming language. Originally designed as a high level scripting language for producing dynamic Web pages, PHP is used mainly in server-side application software.Task: Install PHPIf you are using Fedora

FreeBSD or BSD reboot and shutdown system

2006-08-22T03:02:00.000+05:30

Q. How do I reboot or shutdown BSD (FreeBSD) based system. Command shutdown -h 0 is not working for me.A. FreeBSD or other BSD uses the shutdown or halt command to shutdown system. To reboot FreeBSD/BSD box use reboot command.Task: Shutdown BSDUse shutdown command to close down the system at a given time. Type following command to shutdown system immediately:# shutdown -h nowOR# haltTask: Reboot

Fedora Core Linux chkconfig does not display service name

2006-08-21T21:18:00.000+05:30

Q. I have server / service is installed but it does not show up in the chkconfig --list output. I need to use full path /etc/init.d/service start. I am using Fedora Core Linux and Cent OS (RHEL based) distos.How do I solve this problem?A. Use --add option to add the service to chkconfig database. For example:# chkconfig --add lighttpdWhere,lighttpd: Service name.Now see the list with the

I2O block arrays trouble - Linux fails to install GRUB at the end of successful installation

2006-08-21T17:16:00.000+05:30

Q. I am using Debian Linux (also tried Cent OS and Fedora Linux/RHEL etc). Linux fails to install GRUB boot loader at the end of successful installation. I am installing on I2O block arrays. Do I need to load something before installing on I2O block arrays?A. I2O controllers comprise many different SCSI (and rarer IDE) RAID controllerssupported by the i2o_block driver. There is a workaround this

Add a package group using up2date command

2006-08-17T03:08:00.000+05:30

Q. How can I add a package group using up2date command?A. Update Agent provides a complete system for updating the RPM packages installed on a Red Hat Enterprise Linux system. Both command line and graphical interfaces are included.Task: Install group packageFor example install all Development Tools package i.e. gcc c/c++ compiler and related libs:Login as root and type the following command:#

Restrict Linux users to their home directories only

2006-08-17T02:00:00.000+05:30

Q. How can I make sure that users can only access their own home directories?A. You can use rbash i.e. restricted bash shell. A restricted shell is used to set up an environment more controlled than the standard shell. It behaves identically to bash with the exception that the following are disallowed or not performed:Changing directories with cdSetting or unsetting the values of SHELL, PATH,

Linux: Verify MD5 checksum of ISO file using Windows XP

2006-08-15T02:25:00.000+05:30

Q. How do verify my MD5 checksum of an ISO file under Windows XP? The Linux ISO images downloaded from the net onto Windows XP system.A. Under Linux or UNIX you can use MD5 checksum command to calculate the MD5 checksum of a file or an ISO image.Under Windows XP and other Windows operating system you need to use a special program called winMD5Sum. It is a simple open source Windows MD5 checke to

How do I start and stop NFS service?

2006-08-15T02:01:00.000+05:30

Q. How do I start and stop NFS service from command prompt? How do I make sure NFS always stars automatically when system boots or restarts?A. Make sure the portmap is running with the following command:# /etc/init.d/portmap startOR# /etc/init.d/portmap restart To start NFS Service type the command:# /etc/init.d/nfs startTo restart NFS Service type the command:# /etc/init.d/nfs restartTo STOP NFS

Formatting usb pen in Linux

2006-08-08T22:26:00.000+05:30

Q. How do I format USB pen in Linux?A. You can use standard mke2fs command to format usb pen in Linux. mke2fs is used to create an ext2/ext3 filesystem (usually in a disk partition or other USB devices). device is the special file corresponding to the device (e.g /dev/hdXX). blocks-count is the number of blocks on the device. If omitted, mke2fs automagically figures the file

Howto find out or Learn harddisk size in Linux or UNIX

2006-08-08T22:16:00.000+05:30

Q. How do I find out or learn hard disk size in Linux?A. Under Linux and UNIX you can use df command. df command displays the amount of disk space available on the file system containing each file name argument. If no file name is given, the space available on all currently mounted file systems is shown.Task: Display hard disk partition size$ dfOutput:Filesystem 1K-blocks

How do I use shell aliases under Linux?

2006-08-08T01:09:00.000+05:30

Q. What is a shell alias and how do I use them under Linux?A. An alias is nothing but a short form of a Linux or UNIX command. You use aliases to save the time. To create an alias use the alias command.Task: Display current aliasesType alias command with no arguments or with the -p option prints the listof aliases in the form alias NAME=VALUE on screen:$ aliasOutput:alias cp='cp -i'alias l.='ls -

Linux and UNIX view command-line history

2006-08-06T22:08:00.000+05:30

Q. How do I view command line history? I am Cent OS.A. BASH is the default shell for Linux computers. Bash has history command. It display the history list with line numbers i.e. it lists everything you have entered on the command line. You can recall commands from history so that you can save the time.Task: View your command Line HistoryType the following command:$ historyOutput:911 man 7

Linux setup default gateway with route command

2006-08-02T19:26:00.000+05:30

Q. How do I setup default gateway with a route command?A. route command show and/or manipulate the IP routing table under Linux and UNIX oses.Route manipulates the kernel’s IP routing tables. Its primary use is to set up static routes to specific hosts or networks via an interface after it has been configured with the ifconfig program. When the add or del options are used, route modifies

Why my Apache Server Side Include (SSI) is not working?

2006-08-02T18:24:00.000+05:30

Q. I would like to use Server Side Include (SSI) from my html pages. But it is not working for VirtualHost. How do I configure Apache Server Side Include?A. From Aapache site, "SSI (Server Side Includes) are directives that are placed in HTML pages, and evaluated on the server while the pages are being served. They let you add dynamically generated content to an existing HTML page, without

Kill process in Linux or terminate a process in UNIX or Linux systems

2006-08-01T00:30:00.000+05:30

Q. How do I kill process in Linux?A. Linux and all other UNIX like oses comes with kill command. The command kill sends the specified signal (such as kill process) to the specified process or process group. If no signal is specified, the TERM signal is sent.Kill process using kill command under Linux/UNIXkill command works under both Linux and UNIX/BSD like operating systems.Step #1: First, you

How reduce or shrink Logical Volume on Linux

2006-08-01T00:05:00.000+05:30

Q. How do I reduce or shrink Logical Volume on Linux? I am using CentOS Linux. Moreover, I would like to shrink or reduce a partition on an existing Logical Volume.A. You need to use e2fsadm command. This command allows you resizing of a logical volume containing a mounted or unmounted ext2/ext3 filesystem. Logical volumes can be resized dynamically while preserving data on the volume for both

Iptables is not sending LOG to syslog file

2006-07-30T22:16:00.000+05:30

Q. I am running SSH/MySQL/Webserver and setup iptables based firewall. But my logs are send to console rather than the system log files. How do make sure that iptables LOG target messages are send to /var/log/messages file?A. IPTABLES LOG module turns on kernel logging of matching packets. When this option is set for a rule, the Linux kernel will print some information on all matching packets

Linux or UNIX securely copy files across a network computer

2006-07-30T21:51:00.000+05:30

Q. FTP is insecure, how do I securely copy files across a network computer? My network has Windows and Linux systems.A. You need to use Openssh client and server technology to copy between two more network computers. You can also find free ssh client tools. scp copies files between hosts on a network. It uses ssh for data transfer, and uses the same authentication and provides the same security

What ports need to be open for Samba to communicate with other windows/linux systems?

2006-07-29T23:23:00.000+05:30

Q. What ports need to be open for Samba to communicate with other windows/linux systems? I need to configure Linux firewall so I need the exact port names.A. You can get list of ports from file called /etc/services. For your ease of use here are ports you need to open for two-way samba communication with Windows and Linux desktop systems.netbios-ns - 137/tcp # NETBIOS

Ubuntu Linux enable telnet service

2006-07-29T23:14:00.000+05:30

Q. How do I start telnet service under Ubuntu Linux?A. Telnet is an insecure service. It is recommended that you use ssh service. However sometime telnet server or service is needed. Here are instructions to enable telnet:Install telnetd server$ sudo apt-get install telnetdRestart inetd service:$ sudo /etc/init.d/inetd restartYou should now be able to telnet to the server from Windows or Linux

How do I start Oracle service in UNIX?

2006-07-29T23:07:00.000+05:30

Q. How do I start Oracle service in UNIX? I am using Solaris UNIX.A. In order to start Oracle service in UNIX you need to login as Oracle user. Use su – command:$ su - oracleNow use lsnrctl command to start service (usually located at /home/oracle/oracle/product/10.2.0/db_1/bin directory):$ lsnrctl startNext start database:$ dbstartTo stop Oracle service in UNIXTo stop Oracle servuice type

Linux mount and access a compact flash card - howto

2006-07-29T03:19:00.000+05:30

Q. I have a compact flash card reader hardware device connected to USB port of computer system. Now how do I mount and access a compact flash card connected to this Linux system (Fedora Core)?A. Your compact flash card will automatically detected by Linux. First create a mount point (type the following command as root user):# mkdir -p /mnt/cflashcardIf you don’t have any SCSI device, your first

How can I restore a backup of a MySQL database?

2006-07-29T02:58:00.000+05:30

Q. I made MySQL backup using mysqldump-u user -h localhost -ppassword forumdb | -gzip -9 > forumdb.sql.gz command. How do I restore backup MySQL database?A. mysqldump command is text-based client or tool for dumping or backing up mysql databases, tables and or data. You can use same command as follows:$ gunzip forumdb.gzNow restore using mysqldump$ mysqldump -u user -h localhost -ppassword

Linux display CPU information - number of CPUs and their speed

2006-07-29T02:38:00.000+05:30

Q. How do I display CPU information such as the number of CPUs and their speed?A. Proc (/proc) file system provides easy information about CPU and their speed.The proc filesystem is a pseudo-filesystem which is used as an interface to kernel data structures. It is commonly mounted at /proc. Most of it is read-only, but some files allow kernel variables to be changed.You need to use /proc/

Linux Force fsck on the next reboot or boot sequence

2006-07-23T20:02:00.000+05:30

Q. I want to force fsck on the next reboot? How do I force fsck? Is there any configuration file that I need to alter....A. fsck is used to check and optionally repair one or more Linux file systems. You don’t have to create or alter/modify any file. All you need to do is just create empty file /forcefsck.By creating /forcefsck file you will force the Linux system (or rc scripts) to perform a

Linux Setting up a software RAID1 system for a complete mirror

2006-07-23T19:51:00.000+05:30

Q. How do I setup a software RAID1 system for a complete mirror? I am using Cent OS Linux distribution,A. You can setup a software RAID during installation. However for some reason if you cannot setup RAID 1 during installation, then consider reading this tutorial. It explains how to setup a RAID 1 on a running system.

Linux log files location and how do I view logs files?

2006-07-17T23:40:00.000+05:30

Q. I am new to Linux and I would like to know where are the log files located under Debian or Cento OS Linux server? How do I open or view log files?A. Almost all logfiles are located under /var/log directory (and subdirectory). You can change to this directory using cd command but you need to be the root user. You can use less, more, cat or tail command to see the logs.Go to /var/logs directory:

Disable graphical GRUB splash screen

2006-07-17T23:04:00.000+05:30

Q. I don't like the graphical GRUB splash screen provided by SUSE Linux. How do I disable graphical GRUB splash screen?A. You can disable your graphical splash or boot screen. All you need to do is edit the grub.conf or grub.lst file located at /boot/grub/grub.confOpen grub.conf using text editor:# vi /boot/grub/grub.confNow find the line which starts with the word splashimage and comment it out

Iptables setup masquerading for Linux firewall

2006-07-15T01:19:00.000+05:30

Q. How do I setup masquerading for my Linux iptables firewall? What rules I need to apply or write?A. Iptables is used to set up, maintain, and inspect the tables of IP packet filter rules in the Linux kernel. Several different tables may be defined. Each table contains a number of built-in chains and may also contain user-defined chains. However, to setup masquerading you need to use

Qmail allow email from my own domain (particular domain) only

2006-07-14T16:24:00.000+05:30

Q. How do I allow receiving email from my own domain only? I am using Qmail mail server software under Fedora Core Linux.A. You can change the behavior of the qmail system by modifying qmail's control files. This is essential as you do not want to become a source of open mail relay. By default qmail will not relay. However every persons need is different. You can force qmail to accept domain

Qmail delivering mail ~/Mailbox home directories

2006-07-13T16:31:00.000+05:30

Q. I have installed and configured qmail successfully. Everything is working fine except that mail for loacal user can not be read using mail command. How do I fix this problem?A. If you are delivering mail into ~/Mailbox for each user instead of /var/mail directory, you need to setup few things so that mail can read using mail and other command line tools.Type following command at shell prompt:$

Analog Input: Cannot display this video mode error and solution

2006-07-12T00:20:00.000+05:30

Q. I am getting following error:Analog Input: Cannot display this video mode.What is the meaning of this error and How do I fix it?A. This error indicates that current monitor refresh rate is not correct i.e out of monitor range. You need to consult monitor manufacturer to get correct refresh rate values (visit web site or read manual). Once you got the correct values, reconfigure your monitor (X

How do I permanently erase hard disk?

2006-07-10T21:01:00.000+05:30

Q. I am going to sell my laptop soon. Before discarding my system, I want to make sure that no one should able to use my personal data using any method (format do not work). Is there any open source software out there that can help me permanently erase my hard disk?A. You can use standard dd command. But I recommend using shred command.Step # 1: First, download knoppix Live CD. Step #2 : Boot

Default username created during a new installation of Linux?

2006-07-08T00:14:00.000+05:30

Q. I am new to Linux. After installing Fedora Core 4, it is prompting for username and password at GUI window Login screen. I don’t want to install Linux again. What is the default username created during a new installation of Fedora Core Linux?A. It is created for system admin account called root and the password you entered during installation is for root user.Username: rootPassword: Password

Linux performance tools to troubleshoot problem

2006-07-06T17:57:00.000+05:30

Q. I am new to Linux. What tools or commands are recommended to troubleshoot performance related problems?A. Following are the basic or essential tools that every Linux or UNIX system admin should be aware of:a) topb) sarc) vmstatd) iostate) freetop commandThe top program provides a dynamic real-time view of a running system. It can display system summary information as well as a list of tasks

Linux Move a print job from one queue to another

2006-06-29T18:00:00.000+05:30

Q. I have two queues. Under Windows it is very easy to move a print job from one queue to another. But how do I move a print job from one queue to another under Linux computer or server?A. You need to use lpmove command which is use to move a job or all jobs to a new destination i.e. from one queue to another queue. Job can be the job ID number or the old destination and job ID.For example, if

Warning, got duplicate tcp line - netstat error and solution

2006-06-28T13:11:00.000+05:30

Q. Whenever I run netstat command it bumps be back with an error, which read as follows:tcp 0 0 ip-201-19-xxx-xxx.ip.s:http adsl-71-129-54-230.dsl:2249 TIME_WAITtcp 0 0 ip-201-19-xxx-xxx.ip.s:http ca-dstreet-cuda3-c6a-5:4380 TIME_WAITtcp 0 0 ip-201-19-xxx-xxx.ip.s:http ip72-199-249-17.sd.sd.:1845 TIME_WAITtcp 0 0 ip-201-19-xxx-xxx.ip.s:http

Adding a user to a Samba (SMB) share

2006-06-23T19:25:00.000+05:30

Q. I am using Fedora Linux and I would like to add a user called joe to Samba. How do I add a user SMB share?A. The procedure is as follows:First add Linux/UNIX user using useradd/adduser command.Then use same user name to add to Samba share using smbpasswd command.Step # 1: Add a user joe to UNIX/Linux systemadduser command adds user to the system according to command line options and

Ubuntu Linux How do I install .deb packages?

2006-06-22T21:06:00.000+05:30

Q. I am new to Ubuntu Linux. I need to install a package called package.deb. I know I can use Synaptic package management to install packages from CD or Internet. But I want to install this special .deb file. So how can I install package?A. You need to use dpkg package manager from shell/command prompt. dpkg is a tool to install, build, remove and manage packages.To install package called

Ubuntu Linux: How to reconfigure X windows system (X.org server)

2006-06-22T20:56:00.000+05:30

Q. I had messed up my Ubuntu Linux X windows configuration by editing files. Now all I want is my default settings back to previous state. How do I reconfigure X.org windows system?A. You need to use dpkg-reconfigure command which reconfigures packages after they have already been installed. Pass it the names of a package or packages to reconfigure. It will ask configuration questions, much

Solaris backspace key issue problem and solution

2006-06-22T14:05:00.000+05:30

Q.When you telnet from Solaris 9 to other UNIX box the backspace key does not work. This is not at all convenient to me. How do I fix this issue?A. You need to use tty command which is use to change and print terminal line settings.Type the following commands:$ stty intr$ stty erase$ stty echoeNow your backspace key should work.See also:Read the man page of stty for more information.

How do I verify that service is turned on in xinetd under Fedora or Red Hat Linux?

2006-06-21T01:11:00.000+05:30

Q. I am running Fedora Linux version 4.0 server. Couple of services run under xinetd. Now how do I verify that service is turned on in xinetd?A. You can use command line tool called chkconfig or text based GUI tool called ntsysv. For example see if service foo:# chkconfig --list fooOutput:foo offAs you see service foo is off, to turn on type command:# chkconfig foo on# chkconfig --list

Sendmail blocking spam email id, ips with access database

2006-06-20T16:31:00.000+05:30

Q. How do I block some1@domain.com or IP address for Sendmail spammers?A. Sendmail offers various options to block an email address, domain name or IP address using access database.File /etc/mail/access act as an access control for your Sendmail smtp server. With this file you can define:Who we accept mail fromWho we accept relaying fromWho we will not send to etcConfiguration# vi /etc/mail/

How can I setup 1920x1200 resolutions for XFree86?

2006-06-17T17:39:00.000+05:30

Q. I would like to setup 1920x1200 resolution for my XFree86 X windows system. How do I setup in XFree86? I am using Fedora Linux v5.0.A. XFree86 is an X server that was originally designed for UNIX and UNIX like (BSD/Linuix) operating systems running on Intel x86 hardware. It now runs on a wider range of hardware and OS platforms.File /etc/X11/XF86Config is a server configuration file

Delete or remove a directory Linux command

2006-06-08T18:38:00.000+05:30

Q. I am new to Linux and command line. How do I delete or remove a directory?A. Use rmdir command. This command remove the DIRECTORY(ies), if they are empty. For example type following command to remove /tmp/docs directory:$ rmdir /tmp/docsIf directory is not empty you will get an error:$ rmdir lettersOutput:rmdir: letters: Directory not emptyYou can chage directory to find out files:$ cd letters

Linux setup a Concurrent Versioning System (CVS) howto

2006-06-07T14:13:00.000+05:30

Q. I am planning to use Concurrent Versioning System. I am using both Red Hat and Fedora Linux. How do I setup a CVS server?A. Concurrent Versioning System (CVS) a widely used version control system for software development or data archiving solutions.From the wiki page, "CVS keeps track of all work and all changes in a set of files, typically the implementation of a software project, and allows

Avoid typing sudo on Ubuntu Linux

2006-06-04T18:47:00.000+05:30

Q. How do I disable sudo command? I prefer old way to become super-user i.e use of 'su -' command.A. New Ubuntu Linux v6.06 (LTS) Server is here and one of the annoying feature is use sudo (which is good for Desktop systems) for each command. On a dedicated Linux server I prefer to use su to become a super user and then run command and log out.So after installation type following commands to

Ubuntu Linux OpenSSH Server installation and configuration

2006-06-04T13:07:00.000+05:30

Q. I have just installed Ubuntu 6.06 and I would like to allow remote login to my system from home via ssh. How do I install and configure SSH server?A. OpenSSH is a FREE version of the SSH connectivity tools that technical users of the Internet rely on. Users of telnet, rlogin, and ftp may not realize that their password is transmitted across the Internet unencrypted, but it is. OpenSSH encrypts

Linux creating or adding new network alias to a network card (NIC)

2006-06-02T13:55:00.000+05:30

Q. I would like to create alias for my network card (NIC) i.e. How do I setup 2 IP address on One NIC? or How do I add alias?A. Linux allows you to add additional network address using alias feature. Please note that all additional network IP address must be in same subnet. For example if your eth0 using 192.168.1.5 IP address then alias must be setup using 192.168.1.0/24 subnet.Using ifconfig

Error /dev/hdX does not have any corresponding BIOS drive and Solution

2006-05-28T14:03:00.000+05:30

Q. After windows XP installation I lost my Grub boot loader and now when I try to run grub-install command to restore Grub in master boot record. But I am getting an error that read as follows: /dev/sda does not have any corresponding BIOS driveHow do I fix this problem?A. grub-install is use to install GRUB on your drive. If you are getting error then try to recheck device map. Type the command

Making changes to /proc filesystem permanently

2006-05-27T17:16:00.000+05:30

Q. How do I make changes to /proc filesystem permanently? For example I want to se fs.file-max to 65536, I can use command echo “65536” /proc/sys/fs/file-max. But, after rebooting my Linux server this value will be reset to the default. How do I make it permanent?A. You are right. You are using sysctl. It is used to modify kernel parameters at runtime. The parameters available are those

Howto rebuilding a RAID array after a disk fails

2006-05-27T16:44:00.000+05:30

Q. I have two disk-mirrored array, suppose if one of my disk in mirrored RAID array fails, then I will replace that disk with new one (I have hot swapping SCSI drives). Now question is how I rebuild a RAID array after a disk fails.A. A redundant array of inexpensive disks, (redundant array of independent disks) is a system, which uses multiple hard drives to share or replicate data among the

How do I use MSN or Yahoo or ICQ instant messaging under Linux?

2006-05-26T18:06:00.000+05:30

Q. I have lots friends most of them use MSN, ICO or Yahoo for chatting purpose. So how do I chat using Linux?A. You need to use Gaim messenger. It is an instant messenger that supports many commonly used instant messaging systems including:YahooMSNICQJabberInternet Relay Chat and others (see complete list)Gaim supports plugins for RSA and GPG encryption, as well as Off-the-record messaging.Gaim

MySQL error 28 and solution

2006-05-25T01:04:00.000+05:30

Q. I am getting an error that read as follows:MySQL: got error 28 from server handlerHow do I fix this problem?A. This error means no space left on hard disk. According to official MySQL docs, “If you get his error, you need to check all filesystems where MySQL operates. It may be single filesystem or as we recommend you can have datadir, tmpdir and log files split into dedicated filesystems.”

How do I move spam mail to spam folder?

2006-05-25T00:49:00.000+05:30

Q. I want to move all mails tagged as spam to "spam" folder. How do I configure it?A. If you have Procmail and Spamassassin installed, then you can move mails using Procmail. It is a mail delivery agent (MDA) or mail filter, a program to process incoming emails on a computer, widely used on Unix systemsOpen ~/.procmail file:$ vi ~/.procmailAppend following lines:# All mail tagged as spam is

Mounting windows partition onto ubuntu Linux

2006-05-23T00:40:00.000+05:30

Q. How do I mount NTFS or FAT paritions under ubuntu Linux?A. You can mount NTFS or FAT windows partition with mount command.Click on ApplicationsSelect AccessoriesSelect TerminalNow terminal window will be on screen.First you need to create directory where you can attach windows partition using mount command (for example /media/c for C:):# sudo mkdir –p /media/cNow find out list of partition (

unmount: /cdrom device is busy error and solution

2006-05-23T00:01:00.000+05:30

Q. I am trying to unmount remotely hosted Linux server. I have CD mounted and when ever I type command umount /cdrom or umount /dev/cdrom I get an error that read as follows:unmount: /cdrom device is busyHow do I solve this problem?A. In order to solve this problem. Run umount command as follows:# cd /# umount /cdromIf problem still continues then forcefully unmount the cdrom:# cd /# fuser -km /

Increase the number of telnet sessions allowed

2006-05-22T23:42:00.000+05:30

Q. I am using Fedora Linux and it act as telnet server for our University UNIX lab. We have total 250 computers. At a pick time more than 100 people try to connect server. Only 90 connections are allowed (configured by old admin). Now I want to take this limit to 300 connections or instances. How do I increase the number of telnet sessions allowed?A. Under Fedora Linux (and old Red Hat Linux or

Access NAS server using NFS protocol under Linux or UNIX

2006-05-21T17:31:00.000+05:30

NFS (Network File System) is a protocol originally developed by Sun Microsystems. NFS used by UNIX and Linux oses as a distributed file system which allows a computer/server/workstation to access files over a network.NFS is a popular file-sharing protocol for Linux and UNIX. NAS (Network attached storage) also supports NFS configuration. In order to use NFS you need to run portmap service and

Access NAS server using Windows 2000 or 2003 server

2006-05-19T18:18:00.000+05:30

As I said earlier, Network Attached Storage (NAS) commonly used to store backup and other shared files over TCP/IP network. Use following instructions to configure windows 2000 or 2003 server client:Using Windows ExplorerOpen MS-Windows Explorer.On the Tools menu, click Map Network Drive.Select a drive letter in the Drive box In the Folder box, type the UNC path for the NAS server (\\server

How do I access NAS server using automount?

2006-05-19T17:54:00.000+05:30

Network-attached storage commonly used to store backup and other shared files over TCP/IP network. For example:i) Corporate e-mail system with multiple, load-balanced webmail serversii) Load-balanced web servers access the same contents from NAS storageiii) Backup files or dumps to NAS storage from all other servers using FTP/NFS/CIFS.Autofs is a automounter for Linux. It allows:a) Mount your

Linux add a swap file howto

2006-05-18T16:14:00.000+05:30

Q. I need additional swap space to improve my system performance. How do I add a swap file to Linux system?A. You can add swap file as a dedicated partition or use following instructions to create a swap file.a) Login as the root userb) Type following command to create 512MB swap file (1024 * 512MB = 524288 block size):# dd if=/dev/zero of=/swapfile1 bs=1024 count=524288c) Set up a Linux swap

How do I update Ubuntu Linux softwares?

2006-05-18T15:58:00.000+05:30

Q. I have latest version of Ubuntu Linux. How do I update Ubuntu Linux for security and application fix or upgrades?A. Ubuntu Linux can be upgraded using GUI tools or using traditional command line tools.Using apt-get command line toola) Open terminal and type following two commands:b) Get update software list: $ sudo apt-get updatec) Update software(s) i.e. apply updates: $ sudo apt-get upgraded

PHP not connecting to a MySQL database server

2006-05-16T18:01:00.000+05:30

Q. I have Apache Web server and MySQL configured. Everything works fine except I am not able to connect to a MySQL database server (I am able to connect mysql server with mysql client). So how do I configure or connect PHP scripts?A. You need to install MySQL module for php4 or php5. Without this scripts you will be not able to connect to MySQL database server.If you are using Debian LinuxTo

Linux Virtual Private Network setup

2006-05-16T17:45:00.000+05:30

Q: What software program do I have to use under Linux for Virtual Private Network (VPN)?A: A virtual private network (VPN) is a private communications network. It provide a secure connection through an otherwise insecure network, typically the Internet. VPNs are generally cheaper than real private networks using private lines but rely on having the same encryption system at both ends.Linux

Linux reset forgotten root password

2006-05-13T12:59:00.000+05:30

Q. I forgot my root password, how can I get into my system?A. You can reset forgotten root password under Linux by booting system into single user mode or emergency mode (also known as rescue mode).My boot loader is GRUB (see LILO boot loader below)Following is the procedure to reset root password if you are using GRUB as a boot loader:Select the kernelPress the e key to edit the entrySelect

Linux copy data from a floppy to hard disk

2006-05-13T10:11:00.000+05:30

Q. How do I copy files from a floppy disk to my hard disk. I am using a 1.44 MB floppy.A. /dev/fd0 is your first floppy disk drive (/dev/fd1 is second and so on) under Linux. You need to use normal mount command. All files accessible in a Unix system are arranged in one big tree, the file hierarchy, rooted at /. These files can be spread out over several devices. The mount command serves to

Linux setting hostname and domain name of my server

2006-05-12T11:14:00.000+05:30

Q. I would like to change hostname and domain name for my Linux server. Where can I set the local hostname and domain name of my server?A. You can use hostname command to show or set the system's host name and dnsdomainname command to show the system's DNS domain name. But the changes are temporary if you use these commands.Local hostname and domain name of your server defined in text

FreeBSD Accessing the CDROM drive from the command line

2006-05-10T20:49:00.000+05:30

Q. How do I mount the CDROM from FreeBSD shell or command line?A. You need to use mount command. The mount utility calls the mount(2) system call to prepare and graft a special device or the remote node (rhost:path) on to the file system tree at the point node. If either special or node are not provided, the appropriate information is taken from the fstab(5) file.In most cases /etc/fstab lists

Windows server display current TCP connections

2006-05-10T18:33:00.000+05:30

Q. I would like to find out all current connections to my windows 2000/2003 server. How do I display current connections?A. Microsoft Windows networking tools include netstat command. It is use to to displays active TCP connections, ports on which the computer is listening, Ethernet statistics, the IP routing table, IPv4 statistics (for the IP, ICMP, TCP, and UDP protocols), and IPv6 statistics (

Securing MySQL server

2006-05-10T18:19:00.000+05:30

Q. I am using MySQL database server and my question is how do I secure mysql server?A. If you are using MySQL on a computer connected to the Internet then you need to secure MySQL server to avoid the most common security mistakes.Official MySQL site has a section that describes some general security issues to be aware of and what you can do to make your MySQL installation more secure against

Steps for compiling Linux kernel on SMP Itanium IA64 system

2006-05-09T16:33:00.000+05:30

Q. I would like to know howto compile Linux kernel on SMP Itanium IA64 system. Is it possible?A. Yup it is possible to compile Linux kernel as it is one of the supported platform. Read the README file located in /usr/src/linux* directory. Here are quick steps:# cd /usr/src/linux-version# make clean# make mrproper# make menuconfig# make dep# make# make modules# make install# make modules_installIn

How does SNMP work?

2006-05-04T16:58:00.000+05:30

The simple network management protocol (SNMP) use for monitoring of network-attached devices for any conditions that warrant administrative attention. It is use to manage IP network devices such as servers, routers, switches etc. Administrator can find or manage network performance, solve problem or even optimize it further.You can find out many resources on the net that explain SNMP. Take a look

Linux partition naming convention and IDE drive mappings

2006-05-04T16:43:00.000+05:30

Q. I am new to Linux and I not able to understand /dev/hdc (is it C: drive?) under Linux. This is quite confusing for a new Linux user like me. What device naming convention followed by Linux? Can you explain it in layman's term?A. Linux does not follows DOS or Windows XP style partition names or drive names. It is true that it is a bit confusing for a new Linux user. Linux use combination of bus

File size limit exceeded error under Linux and solution

2006-05-04T16:13:00.000+05:30

Q. I am trying to copy a file called act.dat and I am getting an error ‘file size limit exceeded’ under Linux. How do I get rid of this error? In addition, I do have enough disk space to copy this file.A. Your system administrator must have imposed limitation on your account for file size creation.. Just run ulimit command to find out file size limitation:$ ulimit -aOutput:core file size

Disable the mail alert by crontab command

2006-05-04T15:56:00.000+05:30

Q. How do I to disable the mail alert send by crontab? When my job is executed and the jobs cannot run normally it will sent an email to root.A. crontab command is use to maintain crontab files for individual users.By default the output of a command or a script (if any produced), will be email to your local email account. To stop receiving email output from crontab you need to append following

Error: Couldn't open display (null) and solution

2006-05-03T16:56:00.000+05:30

Q. I am trying to run X applications using secure shell (SSH). I connect to my server using ssh myserver.com. But when I run X application it dump me back with an error as follows:Error: couldn't open display (null).How do I fix this problem?A. You are trying to use ssh X11 X11 forwarding. To enable X11 forwarding you need to pass either the -Y or -X options to SSH command. For example try:$ ssh

How do I save iptables rules or settings?

2006-05-03T16:45:00.000+05:30

Q. I am using GUI tool to setup rules for my home computer connected to ADSL (DSL/Cable) network. However after reboot my rules are not there. Is there any way I can save and load them again.A. You need to use iptables-save command which is used to dump the contents of an IP Table in easily parseable format to screen. Using I/O-redirection provided by your shell you can save iptables firewall

GUI Tools for managing MySQL databases server

2006-05-03T16:17:00.000+05:30

Q. I am new to both Linux and MySQL database server. Can you provide any name og GUI tools for managing MySQL databases server remotely as well as locally?A. MySQL has various GUI tools for managing MySQL databases server remotely as well as locally. However not all software are free. Here are two best free tools:MySQL Administrator – It is a powerful visual administration console that enables

Linux Kernel panic VFS Unable to mount root fs and solution

2006-05-03T14:51:00.000+05:30

Q. I am using Linux on HP server and I am getting error that read “Linux Kernel panic: VFS: Unable to mount root fs ….”. How do I solve this problem?A. Most modern distributions including Debian uses loadable kernel module for ext3 file system. So to read ext3/ext2 file system kernel must load ext3 kernel module (ext3.ko).This module is included in an initrd image. If an initrd image is missing

Linux change the speed and duplex settings of an Ethernet card

2006-05-02T16:50:00.000+05:30

Under Linux use mii-tool or ethtool package which allows a Linux sys admin to modify/change and view the negotiated speed of network interface card (NIC) i.e. it is useful for forcing specific Ethernet speed and duplex settings.Depending on which type of Ethernet card is installed on the system you need to use either mii-tool or ethtool. I recommend installing both and use one of the tool, which

Linux mount ntfs or Access NTFS partition from Linux

2006-05-02T16:23:00.000+05:30

Q. How do I access my Windows NT/XP NTFS partition from Linux?A. In order to access NTFS partition you need support compiled into running Linux kernel. You may need to recompile the kernel to include NTFS support.There is a Linux-NTFS project. The goals of the project are to develop reliable and full feature access to NTFS by the Linux kernel driver, and by a user space filesystem (ntfsmount),

Shell script to get the time difference

2006-05-02T13:20:00.000+05:30

Q. I am able to write PHP or Perl script where I can find out time difference between script executions. Now I have .shtml file that is nothing but a shell script outputting some data to browser. What I want is time difference or time it took to execute a script. How do I write a shell script?A. Your Logic should be as follows:* Get start time and store to a variable START* Execute a shell script

Backup home directories in Linux

2006-05-02T12:39:00.000+05:30

Q. I would like to Backup all directories in /home to /dev/st0 tape drive. How do I use script to automate task and what commands do I need to use?A. Use tar command to backup /home directory. The GNU version of the tar archiving utility included with all Linux distributions.For example tar command to backup /home should be as follows:# tar -czf /dev/st0 /homeSince this topic is already covered,

Unreliable Mouse jumps when using a KVM switch in Linux

2006-05-02T11:44:00.000+05:30

Q. I am using a KVM switch (that connects two or more computers to the same keyboard, mouse, and monitor) to connect Linux box but mouse gives the worst user experience. How do I solve this problem?A. You need to setup PS2 mouse protocol extension correctly. This can be done by passing boot time parameter to Linux kernel. Just append following parameter to kernel:psmouse.proto=impsAbove parameter

Unpacking or uncompressing gz files

2006-05-01T20:22:00.000+05:30

The .gz file extension are created using Gzip program which reduces the size of the named files using Lempel-Ziv coding (LZ77).Each file is replaced by one with the extension .gz, while keeping the same ownership modes, access and modification times.To expand i.e. to Unpacking or uncompressing gz files you need to use gunzip program Or gzip -d or zcat program:Using gunzip command:$

Find out if shell command is aliased or not

2006-05-01T12:40:00.000+05:30

Q. Sometime I get confuges whether command is an alias or it is real command. How do I find out if shell command is aliased?A: You need to use type command. It rells whether command is an alias, function, buitin command or executable command file.For example:$ type --all lsOutput:ls is aliased to `ls --color=auto'ls is /bin/lsOR$ type aliasalias is a shell builtinSo for each command, it indicate

Sendmail Limiting Denial of Service (DOS) Attack

2006-05-01T12:26:00.000+05:30

Q. I would like to know configuration directives that will limit Sendmail Denial of Service attack.A. Sendmail is a mail transfer agent (MTA) i.e. that transfers electronic mail messages from one computer to another. It is possible that attacker can flood the mail server with DOS (it is an attack in which no access to the system(s) is gained, but rather a loss of service is incurred i.e. your

Configure rsh so that is does not prompt for a password

2006-05-01T12:06:00.000+05:30

Both rsh or rlogin prompt for a password. All you need to do is open /etc/hosts.equiv file on host system and add entries for all hosts you would like use without password .This file list of hosts and users that are granted "trusted" r (rsh/rloging) command access to your system without supplying a password.$ cat /etc/hosts.equivOutput:job1.ha1.nixcraft.comjob2.ha1.nixcraft.comjob3.ha1.

Turn off selinux (Security-Enhanced Linux)

2006-05-01T11:34:00.000+05:30

Security-Enhanced Linux (SELinux) is security patch applied to Linux kernel. When enabled in the kernel it follows the the principle of least privilege. It is an implementation of mandatory access control using Linux Security Modules (LSM).From Wikipeidia Selinux page:SA Security-enhanced Linux is a set of patches to the Linux kernel and some utilities to incorporate a strong, flexible mandatory

Install Linux on Serial ATA (SATA) drives

2006-04-30T23:40:00.000+05:30

SATA is a computer bus technology for data transfer from hard disk. Linux does support serial ATA. The complete list of supported driver (status report) is hereWhile installing Linux if you don’t see STAT hard drive then go to your BIOS setup. Change the SATA configuration in the BIOS (i.e. legacy ATA mode) so drives are seen as individually, not in RAID setup. In my personal experience, this

How to Scan new LUNs on Linux with QLogic driver

2006-04-30T21:28:00.000+05:30

Q: I am using QLogic driver and I would like to know how do I scan new LUNs on Linux operating system?A: You need to find out driver proc file /proc/scsi/qlaXXX. For example on my system it is /proc/scsi/qla2300/0Once file is identified you need to type following command (login as the root user):# echo "scsi-qlascan" > /proc/scsi/qla2300/0# cat /proc/scsi/qla2300/0Now use the script

Find out if package is installed in Linux

2006-04-30T17:34:00.000+05:30

The command to finding out if package is installed in Linux is depend upon your Linux distribution. Following are commands for different distributions.Jump to your distribution:* Debian Linux* Red Hat / Fedora LinuxDebian LinuxUse dpkg command, which is package manager for Debian. Suppose you want to find out package apache-perl or sudo is installed or not, type command:$ dpkg -s apache-perlOR$

Linux how to find if processor is 64 bit or not

2006-04-30T16:14:00.000+05:30

Q. Quick question, how to determine if CPU is 64bit under Linux?A. You need to use uname command which, print system information including kernel version and whether it has 32 bit or 64 bit CPU. You can also use less /proc/cpuinfo linux command determine if it is 64 bit cpu or not.Example$ uname –aOutput:Linux ora100 2.6.5-7.252-smp #1 SMP Tue Feb 14 11:11:04 UTC 2006 x86_64 x86_64 x86_64 GNU/

Fedora Linux reconfigure X server

2006-04-30T15:46:00.000+05:30

Q. I messed up with my X server configuration. Now I would like to reconfigure X server.A. Fedora comes with the X Configuration Tool called redhat-config-xfree86 which provides a graphical interface for creating, modifying or reconfiguring the XFree86 configuration file.At shell prompt type following command to reconfigure X server under Fedora Linux (login as the root user):#

Open ftp port 21 on windows XP operating system

2006-04-25T20:14:00.000+05:30

MS-Windows XP service pack 2 comes with in build firewall. If Microsoft Windows Firewall is blocking a port that is used by a service or by a program, you can configure the Windows Firewall to create an exception. Windows Firewall may be blocking a program or a service if Programs do not respond to a client's request or you do not get data from server.Open ftp port 21 To open ftp port 21 you need

Configure a system to automount a Samba share with /etc/fstab

2006-04-25T12:02:00.000+05:30

As explained earlier you can use the mount command to mount a remote windows partition or a windows share under Linux./etc/fstab file contains static information about the filesystems. The file fstab contains descriptive information about the various file systems. fstab is only read by programs, and not written; it is the duty of the system administrator to properly create and maintain