zsh学习笔记

已发布 2016-10-27 21:59:30

Configure

Starts up files

  • /etc/zshenv
  • ~/.zshenv
  • IF the shell is a login shell, /etc/zprofile and ~/.zprofile
  • IF the shell is interactive, /etc/zshrc and ~/.zshrc
  • IF the shell is a login shell, /etc/zlogin and ~/.zlogin

Logging out

/etc/zlogout is read, and then ZDOTDIR/.zlogout

Two terms

A login shell is generally one that is spawned at login time. (IE, by either /bin/login or some other daemon that handles incoming connections). If you telnet, rlogin, rsh, or ssh to a host, chances are you have a login shell. An interactive shell is one in which prompts are displayed and the user types in commands to the shell. (IE, a tty is associated with the shell)

For example, if I run the command

ssh SOME_HOST some_command

I will be running (presumably) a non-interactive program called some_command. This means that zsh will not be an interactive shell, and ignore the corresponding files. Zsh should, however, be a login shell, and read the appropriate files.

Zsh options

  • Over 100 options.
  • case-insensitive.
  • underscores are ignored. SOME_OPTION == SOMEOPTION
  1. setopt OPTION_NAME <— Turn an option on
  2. unsetopt OPTION_NAME <— Turn an option off
  3. setopt NO_OPTION_NAME <— Turen an option off too!

Zsh Prompts (提示符)

  • primary: contained in the shell variable PROMPT, also known as PS1
  • IF PROMPT_SUBST is on: the prompts are first subjected to parameter expansion, command substitution, and arithmetic expansion, before actually displays them.

Customize

  • Over 40 special escape sequences to control information
  • current time, date, host info, current directory, etc…

Watching for other users

Events

  • The user who logged in/out: use their username
  • The host where the user was connected from: use @ followed by the remote hostname
  • The line(tty) that the user was connected on: use % followed by the line name(ie, pts/186)

Telling zsh to look for events

watch=all
watch=$USERNAME
watch=(event1 event2 ... eventN)

Obtaining the report

Setting LOGCHECK to interger n will cause zsh to report monitored events every n seconds.(default 60)

Then run log at any time.

Conveniences

Aliases

Every token in the input is checked to see if there is an alias defined for it. If there is, the token will be replaced by the alias value IF:

  • The token is in command position OR
  • The alias is global (See below) OR
  • The previous word on the line was an alias whose value ended in a space.

Using

The formal syntax of the zsh alias builtin is:

alias [ -gmrL ] [ name[=value] ... ]
  • The -r argument tells the alias command to operate on regular aliases.
  • The -g argument tells the alias command to operate on global aliases.
  • Without either the r or g flags, alias operates on both types.

For each name with no value, zsh will print the name and what it is aliased to.

With no arguments at all, alias prints the values of ALL defined aliases

With the -L argument, the output from alias is suitable to cut-and-paste into your startup scripts.

To define one or more aliases, simply enter

alias name1=value1 name2=value2 ... nameX=valueX

For each name with a corresponding value, zsh defines an alias with that value.

Global aliases

zsh lets you use aliases even if they are not the first word on the command line. These kinds of aliases are called global aliases.

alias -g

List aliases that match pattern

alias -m

Disable or delete aliases

  • delete: unalias foo
  • temporarily disable: disable -a foo
  • enable back: enable -a foo

Use the origin command

=ftp or \ftp.

Command cd

cd == chdir

First form

  • cd: cd ${HOME}
  • cd NEW_DIR: Place you in the directory called NEW_DIR
  • cd -: cd ${OLDPWD}

zsh adds some usefull functionality:

First, if zsh doesn’t find NEW_DIR in the current directory (and NEW_DIR isn’t an absolute path), zsh looks at the shell variable cdpath. It looks for a subdirectory NEW_DIR in each directory of cdpath. If zsh sees NEW_DIR, it goes there.

Furthermore, you can store the FULL pathname of directory in a shell variable.

XDIR=/usr/lib/X11
cd XDIR # without the "$"

XDIR is a named directory

Second form

cd OLD NEW

and zsh replaced any occurance of OLD in the current directory with NEW, and then cd’s into it.

Third form

Pull an entry from the direcotry stack.

cd +n
cd -n

dirs -v to see the direcotry stack.

Arguments

All forms of the cd builtin can take a few arguments: - cd -s DIR Don’t cd into DIR if DIR’s path contains symlinks - cd -P DIR Resolve all symlinks to their true values before changing to DIR - cd -L DIR Symlinks are followed, ignoring the CHASE_LINKS option)

Note: Turning on the shell option CHASE_LINKS is the same as the -P argument to cd.

Directory stack

Zsh has an internal directory stack. This is a facility that can help you manage working in many different direcotries throughout your zsh login session.

  • pushd: place onto the direcotry stack
  • popd: get and remove one from the stack top

Command dirs

dirs -v  # view the contents of the stack
dirs dir1 dir2 ... dirN  # rebuild the stack, staring with the rightmost dirN, and push $PWD on the top

popd, pushd

TODO

Filename Expansion and the Directory Stack

Zsh offers a nice way to reference the directory stack quickly in your daily work. The description below is taken directly from the man page:

  • A ~ followed by a number is replaced by the directory at that position in the directory stack.
  • ~0 is equivalent to ~+, and ~1 is the top of the stack.
  • ~+ followed by a number is replaced by the directory at that position in the directory stack.
  • ~+0 is equivalent to ~+, and ~+1 is the top of the stack.
  • ~- followed by a number is replaced by the directory that many positions from the bottom of the stack.
  • ~-0 is the bottom of the stack.
  • The PUSHD_MINUS option exchanges the effects of ~+ and ~- where they are followed by a number.

Brace Expansion

Brace expansion is a convenient feature that allows you to generate lists of items quickly on the command line.

echo str{xx,yy,zz}
echo logfile.1610{01..31}.log

Programing Zsh

Parameters

  • names: can be any sequence of alpha-numeric characters and underscores. (There are a few special cases, namely * , @ , # , ? , - , $ , and !)
  • values: the pieces of information that variables store.
  • Values in zsh can be one of three types: strings, integers, or arrays.

Assigning values

name=value
name=(value1 value2 ... valueN) # array parameter
unset PARAMETER_NAME # delete parameter

Scope

  • Shell functions delimit scope for shell parameters.
  • If you assign a value to a variable that doesn’t exist, the variable gets created in the outermost scope.
  • If a variable X goes out of scope, it gets deleted. (Just like in C).

Positional parameters

  • start with the number 0
  • can go past 9. So $11 is the 11th argument.
  • contain all the positional parameters: &, *, argv

Array Parameters

array_name=(value1 value2 ... valueN)
set -A array_name value1 value2 .. valueN
Single element subscripts

subscripts are used to select one of more individual items from an array. zsh’s mechanism for subscripting into arrays is so powerful, it can be considered superior to many programming languages.

The index are start from 1.

some_array[expr]
ARGV[-2]
Obtaining Multiple Consecutive Elements
some_array[expr1,expr2]

This returns elements (in some_array) starting from expr1, up to and including expr2.

Again, the expressions are evaluated to integers before being used, and negative numbers are used in the same way as descibed above.

Subscripts can be included with variable names inside curly braces…

${friends[2,5]}
Replacing Portions of Arrays
> veg=(lettuce carrot celery tomato onion)
> echo $veg
lettuce carrot celery tomato onion
> veg[4]=(pepper radish)
> echo $veg
lettuce carrot celery pepper radish onion
Subscripting Strings

This item is not quite related to arrays, but it’s too useful to pass up.

Sbscript flags

TODO

Parameter expansion

TODO

Filename generation

TODO

Modifiers

TODO

Filename qualifiers

TODO

Programmable completion

Before proceeding, keep the zshcompctl man page in mind.

Completion refers to zsh’s ability to finish your command lines for you. It comes in many forms. By default, the < TAB > key is bound to a completion command in zsh.

Filenames are the default item to complete on. In zsh, ANYTHING can be completed, including:

  • Filenames
  • Filesystems paths
  • builtin commands
  • external commands
  • aliases
  • shell functions
  • reserved words
  • global aliases
  • disabled hash table elements
  • shell options
  • shell parameter names
  • environment variables
  • named directories
  • key bindings
  • running jobs
  • suspended jobs
  • user names
  • anything else you can imagine - you can program it yourself easily.
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