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 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).
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,
https://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 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).
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.
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).
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
- |
- for matching either of two alternatives
-
~, ^
- 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).
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).
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.