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zshroadmap - informal introduction to the zsh manual The Zsh Manual, like the shell
itself, is large and often complicated. This section of the manual provides some pointers
to areas of the shell that are likely to be of particular interest to new users, and
indicates where in the rest of the manual the documentation is to be found.

WHEN THE SHELL STARTS

When it starts, the shell reads commands from various files. These can be created or
edited to customize the shell. See the section Startup/Shutdown Files in zsh(1).

If no personal initialization files exist for the current user, a function is run to help
you change some of the most common settings. It won't appear if your administrator has
disabled the zsh/newuser module. The function is designed to be self-explanatory. You
can run it by hand with `autoload -Uz zsh-newuser-install; zsh-newuser-install -f'. See
also the section User Configuration Functions in zshcontrib(1).

INTERACTIVE USE

Interaction with the shell uses the builtin Zsh Line Editor, ZLE. This is described in
detail in zshzle(1).

The first decision a user must make is whether to use the Emacs or Vi editing mode as the
keys for editing are substantially different. Emacs editing mode is probably more natural
for beginners and can be selected explicitly with the command bindkey -e.

A history mechanism for retrieving previously typed lines (most simply with the Up or Down
arrow keys) is available; note that, unlike other shells, zsh will not save these lines
when the shell exits unless you set appropriate variables, and the number of history lines
retained by default is quite small (30 lines). See the description of the shell variables
(referred to in the documentation as parameters) HISTFILE, HISTSIZE and SAVEHIST in
zshparam(1). Note that it's currently only possible to read and write files saving
history when the shell is interactive, i.e. it does not work from scripts.

The shell now supports the UTF-8 character set (and also others if supported by the
operating system). This is (mostly) handled transparently by the shell, but the degree of
support in terminal emulators is variable. There is some discussion of this in the shell
FAQ, http://www.zsh.org/FAQ/. Note in particular that for combining characters to be
handled the option COMBINING_CHARS needs to be set. Because the shell is now more
sensitive to the definition of the character set, note that if you are upgrading from an
older version of the shell you should ensure that the appropriate variable, either LANG
(to affect all aspects of the shell's operation) or LC_CTYPE (to affect only the handling
of character sets) is set to an appropriate value. This is true even if you are using a
single-byte character set including extensions of ASCII such as ISO-8859-1 or ISO-8859-15.
See the description of LC_CTYPE in zshparam(1).

Completion
Completion is a feature present in many shells. It allows the user to type only a part
(usually the prefix) of a word and have the shell fill in the rest. The completion system
in zsh is programmable. For example, the shell can be set to complete email addresses in
arguments to the mail command from your ~/.abook/addressbook; usernames, hostnames, and
even remote paths in arguments to scp, and so on. Anything that can be written in or
glued together with zsh can be the source of what the line editor offers as possible
completions.

Zsh has two completion systems, an old, so called compctl completion (named after the
builtin command that serves as its complete and only user interface), and a new one,
referred to as compsys, organized as library of builtin and user-defined functions. The
two systems differ in their interface for specifying the completion behavior. The new
system is more customizable and is supplied with completions for many commonly used
commands; it is therefore to be preferred.

The completion system must be enabled explicitly when the shell starts. For more
information see zshcompsys(1).

Extending the line editor
Apart from completion, the line editor is highly extensible by means of shell functions.
Some useful functions are provided with the shell; they provide facilities such as:

insert-composed-char
composing characters not found on the keyboard

match-words-by-style
configuring what the line editor considers a word when moving or deleting by word

history-beginning-search-backward-end, etc.
alternative ways of searching the shell history

replace-string, replace-pattern
functions for replacing strings or patterns globally in the command line

edit-command-line
edit the command line with an external editor.

See the section `ZLE Functions' in zshcontrib(1) for descriptions of these.

OPTIONS

The shell has a large number of options for changing its behaviour. These cover all
aspects of the shell; browsing the full documentation is the only good way to become
acquainted with the many possibilities. See zshoptions(1).

PATTERN MATCHING

The shell has a rich set of patterns which are available for file matching (described in
the documentation as `filename generation' and also known for historical reasons as
`globbing') and for use when programming. These are described in the section `Filename
Generation' in zshexpn(1).

Of particular interest are the following patterns that are not commonly supported by other
systems of pattern matching:

** for matching over multiple directories

~, ^ the ability to exclude patterns from matching when the EXTENDED_GLOB option is set

(...) glob qualifiers, included in parentheses at the end of the pattern, which select
files by type (such as directories) or attribute (such as size).

GENERAL COMMENTS ON SYNTAX

Although the syntax of zsh is in ways similar to the Korn shell, and therefore more
remotely to the original UNIX shell, the Bourne shell, its default behaviour does not
entirely correspond to those shells. General shell syntax is introduced in the section
`Shell Grammar' in zshmisc(1).

One commonly encountered difference is that variables substituted onto the command line
are not split into words. See the description of the shell option SH_WORD_SPLIT in the
section `Parameter Expansion' in zshexpn(1). In zsh, you can either explicitly request
the splitting (e.g. ${=foo}) or use an array when you want a variable to expand to more
than one word. See the section `Array Parameters' in zshparam(1).

PROGRAMMING

The most convenient way of adding enhancements to the shell is typically by writing a
shell function and arranging for it to be autoloaded. Functions are described in the
section `Functions' in zshmisc(1). Users changing from the C shell and its relatives
should notice that aliases are less used in zsh as they don't perform argument
substitution, only simple text replacement.

A few general functions, other than those for the line editor described above, are
provided with the shell and are described in zshcontrib(1). Features include:

promptinit
a prompt theme system for changing prompts easily, see the section `Prompt Themes'

zsh-mime-setup
a MIME-handling system which dispatches commands according to the suffix of a file
as done by graphical file managers

zcalc a calculator

zargs a version of xargs that makes the find command redundant

zmv a command for renaming files by means of shell patterns.

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