Features of the TCSH Shell
In this article, I will describe some of the main features of TCSH, which I believe make it worth using as the primary log in shell. This article is not meant to persuade bash users to change. I've never used bash, so I know very little about it.
As some of you know, I've created a configuration tool called The Dotfile Generator, http://www.imada.ou.dk/~blackie/dotfile/, which can configure TCSH. I believe that this tool is very handy for getting the most out of TCSH without having to read the manual a couple of times. Therefore, I'll refer to this tool several times throughout this article to show how it can be used to set up TCSH.
The shell is your interface to executing programs, managing files and directories, etc. Though very few people are aware of it, they use the shell frequently in daily work, e.g., completing file names, using history substitution and aliases. The TCSH shell offers all of these features and a few more, which the average user seldom optimizes.
With a high knowledge of your shell's power, you can decrease the time you need to spend in the shell, and increase the time spent on original tasks.
An important feature used by almost all users of a shell is command line completion. With this feature you don't need to type all the letters of a file name—just the ambiguous ones. This means that if you wish to edit a file called file.txt, you may need to type only fi and press the TAB key, and the shell will type the rest of the file name for you.
Basically, one can use completion on files and directories. This means that you cannot use completion on host names, process IDs, options for a given program, etc. Another thing you cannot do with this type of completion is to complete directory names when typing the argument for the command cd.
In TCSH the completion mechanism is enhanced, so that it is possible to tell TCSH which list to use to complete a particular command. For example, you can tell TCSH to complete from a list of host names for the commands rlogin and ping. An alternative is to tell it to complete only on directories when the command is cd.
To configure user-defined completion using The Dotfile Generator (TDG), go to the TDG page completion -> userdefined; this will bring up a page which looks like Figure 1.
For the command name, you tell TDG which command you wish to define a completion for. In this example it is rm.
Next you have to tell TDG to which arguments to the command this completion applies. To do this, press the button labeled Position definition. This will bring up a page, which is split into two parts as shown in Figures 2 and 3.
In the first part, you tell TDG the position definition that should be defined from the index of the argument to be completed (i.e., the one where the TAB key is pressed). Here you can tell it that you wish to complete on the first argument, all the arguments except the first one, and so forth.
2066f3.gifFigure 3. TDG Pattern Definition Page
The alternative to “position-dependent completion” is “pattern-dependent completion”. This means that you can tell TDG that this completion should only apply if the current word, the previous word or the word before the previous word conform to a given pattern.
Now you have to tell TDG which list to complete from. To do this, press the button labeled List. This will bring up a page where you can select from a lot of different lists, e.g., aliases, user names or directories.
Four of the lists you can select from are Commands, Directories, File names and Text files. If you select one of these, only elements from that directory are used.
There are two ways to specify completion from a predefined list. One is to mark the option predefined list, and type all the options in this list.
This solution is a bad idea if the list is used in several places (e.g., a list of host names). In that case, one should select the list to be located in a variable, then set this variable in the .tcshrc file.
|Bitcoin on Amazon! Sort of...||Sep 28, 2016|
|Free Today: September Issue of Linux Journal (Retail value: $5.99)||Sep 27, 2016|
|nginx||Sep 27, 2016|
|Epiq Solutions' Sidekiq M.2||Sep 26, 2016|
|Nativ Disc||Sep 23, 2016|
|Android Browser Security--What You Haven't Been Told||Sep 22, 2016|
- Free Today: September Issue of Linux Journal (Retail value: $5.99)
- Bitcoin on Amazon! Sort of...
- Download "Linux Management with Red Hat Satellite: Measuring Business Impact and ROI"
- Android Browser Security--What You Haven't Been Told
- Nativ Disc
- Epiq Solutions' Sidekiq M.2
- Tech Tip: Really Simple HTTP Server with Python
- Identity: Our Last Stand
- Securing the Programmer
Pick up any e-commerce web or mobile app today, and you’ll be holding a mashup of interconnected applications and services from a variety of different providers. For instance, when you connect to Amazon’s e-commerce app, cookies, tags and pixels that are monitored by solutions like Exact Target, BazaarVoice, Bing, Shopzilla, Liveramp and Google Tag Manager track every action you take. You’re presented with special offers and coupons based on your viewing and buying patterns. If you find something you want for your birthday, a third party manages your wish list, which you can share through multiple social- media outlets or email to a friend. When you select something to buy, you find yourself presented with similar items as kind suggestions. And when you finally check out, you’re offered the ability to pay with promo codes, gifts cards, PayPal or a variety of credit cards.Get the Guide