NAME
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).
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://zsh.dotsrc.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.