Skip to main content

cssh, PuTTYCS - keyboard replicators for clustered administration

If you administer a bunch of identical Linux boxes, and have to run same commands on all of them, say like manual deployments, restarts etc. – you probably log in to each of them manually and run commands. Or at best you would have a script looping through them and executing an ssh on each. However there are times when you need to be interactive on each box, yet run the same and/or series of commands.

In those cases, cssh on Unix (with X) and PuTTYCS on windows are a godsend for any administrator.

cssh (cluster ssh) is a X program written in tk/perl that opens up a specified set of ssh windows(xterm) and can send key strokes to all of them at the same time. A small control window has a text box control, where you type to send the same keystrokes to all ssh windows. It also has options to check/uncheck the window instances to be included for the key strokes to send. Windows can also be added at a later point. They can also be typed in, directly.

Like most Unix programs cssh can be configured extensively including but not limited to the terminal program, geometry, name clusters, etc. with its rc file .csshrc. You can generate a .csshrc file with all the defaults using the following command. And then customize it to your needs.

cssh -u > $HOME/.csshrc

image

PuTTYCS (PuTTY Command Sender) works on top of PuTTY windows, sending commands simultaneously to them. Unlike cssh, however, you will open multiple PuTTY windows separately. PuTTYCS will then *latch on* to all the PuTTY windows. The letters typed in PuTTYCS will not replicated in as they are typed, like in cssh. You have type all you want to type in the command area and press enter. Special keys can also be sent using the buttons below the area.

PuTTYCS can be downloaded from here

image

p.s: due credits to Guy Durand, our very able Linux administrator to give the idea for cssh, which got PuTTYCS in search of a windoze alternative.

Popular posts from this blog

One page Stock

Alright.. That was a long absence. The whole last week I dint blog. I dint go away. I was "occupied". I was learning stock trading. Its very fascinating. I have a good weeeked blog for you all. Here is my experience. I can literally hyper-link every word from the following paragraphs, but I am writing it as simple as I can so you can look up the italicised words in wikipedia . I got a paper trading account from a brokerage firm . You need one brokerage account first. Then it can be an Equity account where all your money is yours or a Margin account , where some of the money is lent by the brokerage firm. Then I get Buying power , which is the dollor value of how much stocks you can buy. I can make profit by simple rules. Buy when Price is low. Sell when price is high. There is another more intersting way of earning money. Selling short . Thats when price is not high, per say, but when are confident that the price WILL go down. then buy back when its lowest. This is what

Appcache manifest file issues/caveats

Application cache (appcache) is a powerful feature in HTML5. However, it does come with baggage. Many (see links below) advocated ferociously against it due to tricky issues it comes with. For someone who is just testing waters, these issues may throw them off grid. Knowing them before hand helps reduce some unpredictable effects.

classpath*: making your Modular Spring Resources

Spring gives multiple options to load XML resources for building contexts. the reference documentation does explain this feature quite well. However, I am taking my shot at explaining the different practical scenarios ( by order of growing modularisation) For Example, A simplest Spring based web Context Loader can be configured with resources like this <context-param> <param-name>contextConfigLocation</param-name> <param-value>applicationContext.xml</param-value> </context-param> <listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> You just need to put applicationContext.xml in WEB-INF/ folder of your webapp. However, Typically an application is n-tiered. You can also have multiple files setup and in relative paths. like <param-value> context-files/applicationContext.xml context-files/dao.xml context-files/service.xml </param-value>