Commit f2299e89 authored by Aidan Gauland's avatar Aidan Gauland

* eshell.text (Command Basics): Removed `Command basics' chapter.

parent 94ee8719
2014-01-02 Aidan Gauland <aidalgol@amuri.net>
* eshell.text (Command Basics): Removed `Command basics' chapter.
2014-01-02 Aidan Gauland <aidalgol@amuri.net>
* eshell.text (What is Eshell?): Add section about what not to use
......
......@@ -74,7 +74,6 @@ Emacs @emph{and} with an interface similar to command shells such as
@menu
* Introduction:: A brief introduction to the Emacs Shell.
* Command basics:: The basics of command usage.
* Commands::
* Expansion::
* Input/Output::
......@@ -202,98 +201,6 @@ Apart from these, a lot of people have sent suggestions, ideas,
requests, bug reports and encouragement. Thanks a lot! Without you
there would be no new releases of Eshell.
@node Command basics
@chapter Basic overview
A command shell is a means of entering verbally-formed commands. This
is really all that it does, and every feature described in this manual
is a means to that end. Therefore, it's important to take firm hold on
exactly what a command is, and how it fits in the overall picture of
things.
@menu
* Commands verbs:: Commands always begin with a verb.
* Command arguments:: Some verbs require arguments.
@end menu
@node Commands verbs
@section Commands verbs
Commands are expressed using @dfn{script}, a special shorthand language
computers can understand with no trouble. Script is an extremely simple
language; oddly enough, this is what makes it look so complicated!
Whereas normal languages use a variety of embellishments, the form of a
script command is always:
@example
@var{verb} [@var{arguments}]
@end example
The verb expresses what you want your computer to do. There are a fixed
number of verbs, although this number is usually quite large. On the
author's computer, it reaches almost 1400 in number. But of course,
only a handful of these are really necessary.
Sometimes, the verb is all that's written. A verb is always a single
word, usually related to the task it performs. @command{reboot} is a
good example. Entering that on GNU/Linux will reboot the
computer---assuming you have sufficient privileges.
Other verbs require more information. These are usually very capable
verbs, and must be told specifically what to do. The extra information
is given in the form of @dfn{arguments}. For example, the
@command{echo} verb prints back whatever arguments you type. It
requires these arguments to know what to echo. A proper use of
@command{echo} looks like this:
@example
echo This is an example of using echo!
@end example
This script command causes the computer to echo back: ``This is an
example of using echo!''
Although command verbs are always simple words, like @command{reboot} or
@command{echo}, arguments may have a wide variety of forms. There are
textual arguments, numerical arguments---even Lisp arguments.
Distinguishing these different types of arguments requires special
typing, for the computer to know exactly what you mean.
@node Command arguments
@section Command arguments
Eshell recognizes several different kinds of command arguments:
@enumerate
@item Strings (also called textual arguments)
@item Numbers (floating point or integer)
@item Lisp lists
@item Lisp symbols
@item Emacs buffers
@item Emacs process handles
@end enumerate
Most users need to worry only about the first two. The third, Lisp lists,
occur very frequently, but almost always behind the scenes.
Strings are the most common type of argument, and consist of nearly any
character. Special characters---those used by Eshell
specifically---must be preceded by a backslash (@samp{\}). When in doubt, it
is safe to add backslashes anywhere and everywhere.
Here is a more complicated @command{echo} example:
@example
echo A\ Multi-word\ Argument\ With\ A\ \$\ dollar
@end example
Beyond this, things get a bit more complicated. While not beyond the
reach of someone wishing to learn, it is definitely beyond the scope of
this manual to present it all in a simplistic manner. Get comfortable
with Eshell as a basic command invocation tool, and learn more about the
commands on your system; then come back when it all sits more familiarly
on your mind. Have fun!
@node Commands
@chapter Commands
......
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