Boy, is the shell powerful. Post: 302803269

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The Lounge What is on Your Mind? Boy, is the shell powerful. Post 302803269 by Corona688 on Monday 6th of May 2013 11:02:07 AM

05-06-2013

Registered User

Quote:

Originally Posted by wisecracker

Reading replies to questions, as an amateur, I have learnt a lot from you pros on here.
The shell in any of its guises is serioulsy poweful.

With so many transient and resident commands at one's disposal is there anything, non-GUI, that cannot be done inside a default shell and terminal?

The deep dark secret of high-level languages is that, even if you treat C/C++ as a dark-ages language and eschew it for java/python/shell/CAML/INTERCAL, nearly all the "Good Stuff" your programs depend on(like SOX, and BASH itself) are actually written in it. It's a powerful enough language to build other efficient languages and language addons, a rare feat; hardly anything would be much good without it.

Second, the shell is a good interface to the UNIX system, but a poor interface to other systems where not everything is a file... Imagine you didn't have utilities like SOX or an external /dev/dsp, how simple would your oscilloscope be then?

Shells are bad at networking. Even though BASH and KSH have some networking built into them these days(via a faked /dev/tcp), try building a network server without C help... You can't do it. Too many things missing.

Another thing the shell is poor at is performance. It's great at summoning other programs to do its work for it... not the greatest if you have to sum 3 million numbers in a flash with no outside help.

It's highly subject to system limits, like the length of a command-line, and the maximum length of an environment variable. You happen to get conveniently big ones in LINUX and OSX but aren't always so lucky.

If you don't have access to install things on your system, you will find the shell very limiting. No sox.

Also, you are using nonstandard capabilities of the BASH shell (i.e. dealing with binary data). Imagine you were forced to use an ancient bourne shell, not bash. I don't think you'd consider it quite as fantastic.

Last edited by Corona688; 05-06-2013 at 12:14 PM..

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platform::shell

platform::shell(3tcl)					       Tcl Bundled Packages					     platform::shell(3tcl)

__________________________________________________________________________________________________________________________________________________

NAME

       platform::shell - System identification support code and utilities

SYNOPSIS

       package require platform::shell ?1.1.4?

       platform::shell::generic shell
       platform::shell::identify shell
       platform::shell::platform shell
_________________________________________________________________

DESCRIPTION

       The platform::shell package provides several utility commands useful for the identification of the architecture of a specific Tcl shell.

       This  package  allows the identification of the architecture of a specific Tcl shell different from the shell running the package. The only
       requirement is that the other shell (identified by its path), is actually executable on the current machine.

       While for most platform this means that the architecture of the interrogated shell is identical to the architecture of  the  running  shell
       this  is  not generally true. A counter example are all platforms which have 32 and 64 bit variants and where a 64bit system is able to run
       32bit code. For these running and interrogated shell may have different 32/64 bit settings and thus different identifiers.

       For applications like a code repository it is important to identify the architecture of the shell which will  actually  run  the  installed
       packages, versus the architecture of the shell running the repository software.

COMMANDS

       platform::shell::identify shell
	      This command does the same identification as platform::identify, for the specified Tcl shell, in contrast to the running shell.

       platform::shell::generic shell
	      This command does the same identification as platform::generic, for the specified Tcl shell, in contrast to the running shell.

       platform::shell::platform shell
	      This command returns the contents of tcl_platform(platform) for the specified Tcl shell.

KEYWORDS

       operating system, cpu architecture, platform, architecture

platform::shell 						       1.1.4						     platform::shell(3tcl)