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Unix: Shell Script Wrapper Examples

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Shell script wrappers can make the *nix command more transparent to the user. The most common shell scripts are simple wrappers around third party or system binaries. A wrapper is nothing but a shell script that includes a system command or utility.

Linux and Unix like operating system can run both 32bit and 64bit specific versions of applications. You can write a wrapper script that can select and execute correct version on a 32bit or 64bit hardware platform. In cluster environment and High-Performance computing environment you may find 100s of wrapper scripts written in Perl, Shell, and Python to get cluster usage, setting up shared storage, submitting and managing jobs, backups, troubleshooting, invokes commands with specified arguments, sending stdout to stdout and stderr to stderr and much more.

In this post, I will explains how to create a shell wrapper to enhance the basic troubleshooting tool such as ping and host. read more...
mail this link | permapage | score:9704 | -nixcraft, June 24, 2012

Linux Iptables Examples

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Linux comes with a host based firewall called Netfilter. It is a set of hooks inside the Linux kernel that allows kernel modules to register callback functions with the network stack. A registered callback function is then called back for every packet that traverses the respective hook within the network stack.

This Linux based firewall is controlled by the program called iptables to handles filtering for IPv4, and ip6tables handles filtering for IPv6. This tutorial list most common iptables solutions required by a new Linux user to secure his or her Linux operating system from intruders. read more...
mail this link | permapage | score:9646 | -nixcraft, December 14, 2011

Beginner Ubuntu Tips

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Twenty-five tips for Ubuntu beginners...
Adding another source for software is easy; once you've installed addrepo, you can do it in the terminal by typing something along the lines of addrepo deb http://mirror2.ubuntulinux.nl/ lucid-seveas all.

If you find new repositories online, they will usually give you the right details to enter. You could also do it graphically by going to 'System | Administration | Software Sources | Third Party Software | Add'. read more...
permapage | score:9435 | -Ray, November 9, 2010

Boxes: Draw Text Mode ASCII-art

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Boxes command is a text filter and a little known tool that can draw any kind of ASCII art box around its input text or code for fun and profit. You can quickly create email signatures, or create regional comments in any programming language. This command was intended to be used with the vim text editor, but can be tied to any text editor which supports filters, as well as from the command line as a standalone tool. read more...
permapage | score:9375 | -nixcraft, June 12, 2012

Tutorial: RHEL 5.3 to 5.4 upgrade

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Red Hat Enterprise Linux v5.4 has been released and available via RHN for immediate update. The new version includes the kernel-based virtual machine (KVM) virtualization, next generation of developer features and tools including GCC 4.4, a new malloc(). Also included clustered, high-availability filesystem to support Microsoft Windows storage needs on Red Hat Enterprise Linux.

This tutorial explains how to upgrade RHEL v5.3 to RHEL v5.4. read more...
permapage | score:9280 | -nixcraft, September 3, 2009

Install new skype in Ubuntu 12.04

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Skype is one of the best Video calling software,owned by Microsoft.Skype offer lot of features like Video call,Direct Phone call,Chatting and more.
Features: http://www.skype.com/intl/en/features/ read more...
permapage | score:9275 | -Linux Tips, April 6, 2012

Tutorial: See Colourised Filesystem Disk Space Usage

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The pydf command displays the amount of used and available space on your file systems, just like df command, but in colors. The output format is completely customizable.

This is a little known tool (python script) that displays the amount of disk space available on the mounted filesystems, using different colours for different types of filesystems. read more...
permapage | score:9217 | -nixcraft, June 23, 2012

PDFedit: A Linux PDF editor

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Adobe Acrobat is a commercial tool for manipulating PDF files. Earlier I was using CUPs - printing system, to export PDF files. I’ve also tried out gv for the same purpose. However, I needed complete editing of pdf documents. My search ended with PDFedit software, which is free and open source editor for manipulating PDF documents. The software available in both GUI and CLI (commandline) interface. read more...
permapage | score:9149 | -nixcraft, December 19, 2007

Make Ubuntu 11.10 multimedia ready

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The Ubuntu Restricted Extras will install Adobe Flash Player, Java Runtime Environment (JRE) (sun-java-jre) with Firefox plug-ins (icedtea), a set of Microsoft Fonts (msttcorefonts), multimedia codecs (w32codecs or w64codecs), mp3-compatible encoding (lame), FFMpeg, extra Gstreamer codecs, the package for DVD decoding (libdvdread4, but see below for info on libdvdcss2), the unrar archiver, odbc... read more...
permapage | score:9064 | -Linux Tips, October 27, 2011

Encrypt directories in Ubuntu with Cryptkeeper

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We can create Encrypted Folder in Ubuntu using Cryptkeeper. Cryptkeeper is a system tray applet for Linux that is designed to provide you with simplified options to create hidden encrypted directories. You can save your important data on the password-protected and encypted directories and access at any time by displaying a hidden folder option in the system tray. read more...
permapage | score:9024 | -Linux Tips, October 14, 2011

iozone Tutorial: Measure Linux Filesystem I/O Performance

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This article gives you a jumpstart on performing benchmark on filesystem using iozone a free Filesystem Benchmark utility.

Following are few situations where you may be interested in performing a filesystem benchmarking.

=> Deploying a new application that is very read and write intensive.
=> Purchased a new storage system and would like to measure the performance.
=> Changing the RAID level and would like to measure the performance of the new RAID.
=> Changing the storage parameters and would like to know the performance impact of this change

(here are some impact canvas prints) read more...
mail this link | permapage | score:8966 | -nixcraft, July 4, 2008 (Updated: April 24, 2012)

Tutorial: Identify Linux bottlenecks with kSar

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The sar command collect, report, or save UNIX / Linux system activity information. It will save selected counters in the operating system to the /var/log/sa/sadd file. From the collected data, you get lots of information about your server such as:

1. CPU utilization
2. Memory paging and its utilization
3. Network I/O, and transfer statistics
4. Process creation activity
5. All block devices activity
6. Interrupts/sec etc.

sar output can be used for identifying server bottlenecks. However, analyzing information provided by sar can be difficult, so use kSar, which can take sar output and plot a nice easy to understand graph over period of time. read more...
mail this link | permapage | score:8924 | -nixcraft, December 16, 2009

Find wireless network speed, signal strength on Linux

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Linux operating systems comes with various set of tools allowing you to manipulate the Wireless Extensions and monitor wireless networks. This is a list of tools used for wireless network monitoring tools that can be used from your laptop or desktop system to find out network speed, bit rate, signal quality/strength, and much more. read more...
permapage | score:8904 | -nixcraft, June 8, 2012

Download: Linux 3D Client for Starship Traders

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[Note: Katrina Kirellii now maintains the Linux and Windows versions of the graphical client. The new code can be downloaded from this page.]

Linux game testers wanted

A new version of the Starship Traders multiplayer strategy game is under development. The new version, ST2, has a 3D interface and includes an X-Window-based client program. ST2 is considerably faster than its WWW predecessor and integrates a graphical display and point-and-click mouse controls with a complete keyboard interface. Linux users are needed to participate in the first test game since no other operating systems are yet supported.

The new server is up and running now and a Linux version of the client is available. The client is a dynamically linked Linux x86 binary and requires the Mesa3D or OpenGL libraries -- which should already be installed on most modern distros. Internet access is also required to play in the test game, of course.

To participate in the game you must download, gunzip, and run the Linux binary as described below. It should connect to the ST2 test game automatically and you will be prompted to log in.

[Here is a screenshot of a sector with a starbase, a planet, a tradingpost, some sector debris, a few fighters, a wormhole, and, if you look closely, a couple of small starships in the lower left quadrant intermixed with the text. This screenshot is with the window at 640x480. For a less cluttered appearance you can click resize -- while playing -- to expand (or shrink) the window.]

Download and setup instructions
  • Right click here
  • select Save ...
  • gunzip sst012.gz (your browser may do this step automatically)
  • chmod 555 sst012
  • ./sst012
... and you should be online.

The source code, released 17 September, 2001, can be downloaded from this page.

The Game

Starship Traders II is a trading and war game set in a universe divided into multiple galaxies. Individual locations within the game, called 'sectors', can contain ports, planets, nebulas, wormholes, and black holes, as well as objects owned by players. Players can park their starships, deploy their fighters, and build starbases in sectors.

Players can earn money ('microbots') by hauling commodities between ports and from planets. These microbots can be used as cash to buy equipment and military hardware at trading posts, or microbots can be used directly in combination with commodities to build fighters or starbases.

Players can deploy fighters and build starbases to guard prime trading territories and valuable sectors or they can use fighters to attack the deployed forces of other players. Players can also attack and destroy the starships of other players that they find.

Players can create teams which are ranked separately from the player standings. Players can apply to a team and the team captain can then either accept or reject the application. Team members can move safely through the fighter and starbase fortifications of their teammates and allied attack-mode starbases will not attack them.

Obviously, as in any multiplayer strategy game, politics and diplomacy can be important. Try to avoid making too many enemies early in the game!

Controls

F1 and F2 will scroll you back and forward in the scrolling portion of the heads-up display. F10, F11, and F12 will select different size windows. Running the client with a -w argument (eg.: sst012 -w) will cause it to load into a normal, resizeable window with the standard borders and window controls. Otherwise, it runs in a full-screen mode which may not include borders.

You can fly around within a sector using the arrow keys and pageup/pagedown. Don't do much of this or you may get lost. As you enter each new sector, you start out in the same relative position that you were in in the previous sector so it's possible to fly far away from the center of a sector and not easily find it again. If that happens, log out and back in to get back to the center of the sector.

Move the mouse over any clickable menu option (those that change color when the pointer is over them) and wait about 2 seconds for a popup tip about that menu item.

There is a log off (quit) command in the menu that logs you out, disconnects from the server, terminates the client, and closes the window. If you go link-dead while playing, however, or are otherwise left with an unresponsive client, press Escape to close the window and terminate the client.

Game play

Routine trading and galaxy exploration can be accomplished with as little effort as clicking Computrade on the heads-up display. You can also click on anything in the top half of the display to select that option. Note that options containing a capital letter can also be selected by pressing the appropriate key. Therefore, pressing the c key is equivalent to clicking Computrade.

Options without a capital letter generally have the hot key designated with parens. For example, "keyboard map (?)" can also be accessed by the '?' key.

Right click on any item in the top half of the heads-up display for a brief explanation of that menu option (and the corresponding keyboard key).

History

Starship Traders II is derived, through a long and meandering lineage, from The Last Resort, which evolved from Tsarwars, itself inspired by Czarwars. Czarwars was a DOS-based BBS game dating back to December, 1986. Czarwars was inspired by Chris Sherrick's version of Trade Wars, which drew it's inspiration from Hewlett-Packard's Star Trader, from The People's Book of Computer Games.

Changlog

5/22/01, v.0.02: Lockup after 5 minutes idle bug fixed
5/24/01, sst004: Menu items change color, Star clusters added
5/24/01, sst005: Popup tips added on clickable items
5/24/01, sst006: Rotating ports
5/26/01, sst007: Bigger, moving fighters, more popup tips
5/26/01, sst008: Moving ships, more popup tips
5/27/01, sst009: All heads-up display items now have popup tips
5/27/01, sst010: Bug fix: resizable window works again
5/29/01, sst011: Colors won't wash out on some displays, cursor added, in-sector movement speed scales better on high-speed displays, bar charts work correctly, bottom line of text doesn't disappear on some window sizes
5/31/01, sst012: minor popup documentation changes
5/12/02, sst012d: bug fix, new menu options added
mail this link | permapage | score:8784 | -Ray, May 12, 2002 (Updated: March 21, 2007)

Linux Tips: Using the Red Hat Rescue Mode

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Red Hat offers up some online instructions for using their boot CD as a rescue disk to recover a corrupted system.
The official Red Hat CD-ROM (disk 1) can serve as a bootable emergency disk for most modern PCs with BIOS that can boot from CD-ROMs. It includes file system tools for emergency system administration. Using this disc you can attempt to recover from file system-related crashes.

When your system crashes due to a power failure or any other dire reasons, you may find your file system to be corrupt, and Red Hat Linux might refuse to boot as normal. In such a case do the following:
read more...
mail this link | permapage | score:8769 | -Ray, October 29, 2003

Install Skype in Ubuntu 11.04

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Skype hasn’t been uploaded to the official partner repository of Ubuntu 11.04 Natty Narwhal. So for those who are trying out Natty out there will need to install Skype from their website. Below is the steps for that. read more...
permapage | score:8727 | -Linux Tips, January 11, 2011

User Auditing on Linux

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A variety of methods exist for auditing user activity in UNIX and Linux environments. Some of them come preinstalled within common distributions, some can be downloaded as freeware, and some are commercially available products. Here are some of the most popular methods for auditing. Each method is described, along with tips for how to make the best use of each method. In addition, guidance is provided to show what type of auditing each method is best suited for. read more...
permapage | score:8716 | -falko, January 2, 2013

Tutorial: Linux PPTP VPN client configuration

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With this tip you will be able to work from home using VPN and that too from Linux / FreeBSD system for the proprietary Microsoft Point-to-Point vpn server.

The Point-to-Point Tunneling Protocol (PPTP) is a method for implementing virtual private networks. It works on Data link layer (#2 layer) on TCP/IP model. PPTP Client is a Linux, FreeBSD, NetBSD and OpenBSD client for the proprietary Microsoft Point-to-Point Tunneling Protocol, PPTP. Allows connection to a PPTP based Virtual Private Network (VPN) as used by employers and some cable and ADSL internet service providers. read more...
mail this link | permapage | score:8690 | -nixcraft, June 13, 2007

Using CVS to Manage Linux Configuration Files

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The average developer spends more time navigating, learning, and debugging configuration files than you'd expect. But you can save that time -- and loads of energy and frustration -- with one of the tools you probably use every day: your CVS tree. Take these tips on backing up, distributing, and making portable your peskiest Linux™ (and UNIX®) config files. read more...
permapage | score:8672 | -Idean Momtaheni, June 15, 2004

Tutorial: MySQL Linux C API

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MySQL database does support C program API just like PHP or Perl API.

The C API code is distributed with MySQL. It is included in the mysqlclient library and allows C programs to access a database.

Many of the clients in the MySQL source distribution are written in C. If you are looking for examples that demonstrate how to use the C API, take a look at these clients. You can find these in the clients directory in the MySQL source distribution.

This tutorial provides a sample MySQL C program and step by step compilation instructions to kick start MySQL programming via C API. read more...
mail this link | permapage | score:8666 | -nixcraft, June 1, 2007
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Articles are owned by their authors.   © 2000-2012 Ray Yeargin