Cool Features of the Z Shell

Who am I?

  • Consultant with Chariot Solutions
  • Developing complex Java/Scala projects
  • User of zsh for the past year+
  • Using tools like Maven and git at the command line

What is the Z Shell?

  • An open-source shell for Linux, BSD, OS X, etc.
  • An alternative to bash, csh, etc.
  • Provides some cool features that I find useful in day-to-day work

Installing zsh 5.x

OS X with Homebrew

% brew install zsh
% brew install zsh-completions

Linux

Install via package manager

Do not panic!

This is the Z Shell configuration function for new users,
zsh-newuser-install.
You are seeing this message because you have no zsh startup files
(the files .zshenv, .zprofile, .zshrc, .zlogin in the directory
~).  This function can help you with a few settings that should
make your use of the shell easier.

You can:

(q)  Quit and do nothing.  The function will be run again next time.

(0)  Exit, creating the file ~/.zshrc containing just a comment.
     That will prevent this function being run again.

(1)  Continue to the main menu.

--- Type one of the keys in parentheses ---

Type 'q' to exit setup program

Cool Features

  • Autocd
  • Autocd + cdpath
  • History search
  • Useful globbing
  • Command autocorrect
  • Command completion
  • VCS info on command prompt
  • Themes
  • Creating completion functions

autocd

Allows changing directory without typing cd

If an entry is not a command, then check if a directory name matches

Enable with 

setopt autocd

Given typical home folders

/Users/MikePigg
├── Applications
├── Desktop
├── Documents
├── Downloads
├── Library
├── Movies
├── Music
├── Pictures
├── Public
├── Sites
└── bin
                    
/Users/MikePigg% Desktop
/Users/MikePigg/Desktop% foo
/Users/MikePigg/Desktop/foo% ~
/Users/MikePigg% Downloads
/Users/MikePigg/Downloads% Documents
zsh: command not found: Documents
/Users/MikePigg/Downloads%

autocd + cdpath

cdpath provides a list of directories to search for autocd completions

I set cdpath to include

  • home directory (~)
  • src directory (~/src)
  • top-level directories for projects I'm working on

cdpath=(~ ~/src ~/src/topsecretclient/awesomeproject)

Enjoying autocd+cdpath

/Users/MikePigg% Desktop
/Users/MikePigg/Desktop% foo 
/Users/MikePigg/Desktop/foo% ~ 
/Users/MikePigg% Downloads 
/Users/MikePigg/Downloads% Documents 
~/Documents 
/Users/MikePigg/Documents%

Apache Felix Example

Felix is Apache's OSGi container implementation

OSGi projects are composed of lots of modules

A Felix checkout has 59 directories roughly corresponding to modules of the system

Felix directories

.
├── bundleplugin
├── bundlerepository
├── commons
├── configadmin
├── coordinator
├── dependencymanager
├── deploymentadmin
├── deviceaccess
├── doap
├── eventadmin
├── examples
├── fileinstall
├── framework
├── framework.security
├── gogo
├── http
├── http.jetty
├── installers
├── io
├── ipojo
├── javax.servlet
    .
    .
    .
├── utils
├── webconsole
├── webconsole-plugins
└── wireadmin

Add Felix to cdpath

cdpath=($cdpath ~/src/felix)

Now I can easily jump to Felix

~% felix
~/src/felix
felix%

Jump between subprojects in Felix

felix% gogo
gogo%
gogo% http
~/src/felix/http
http%
http% webconsole
~/src/felix/webconsole
webconsole%
webconsole% http/bridge
~/src/felix/http/bridge
bridge%

Command History

Like other shells, zsh supports command history

Up arrow is bound to previous, down arrow to next

zsh allows searching in history for previous uses of same command

Enable with

bindkey '^[[A' up-line-or-search
bindkey '^[[B' down-line-or-search

Simple usage scenario

% mvn test
[INFO] Scanning for projects...
                    .
                    .
                    .
% vi FailingTest.java
% mvn<up arrow>

fills in with

% mvn test

Globbing

zsh supports advanced globbing patterns

I particularly like the ** pattern

This gives you more power with tools like grep

List all pom files in felix/http

/Users/MikePigg/src/felix% ls http/**/pom.xml
http/api/pom.xml		http/proxy/pom.xml
http/base/pom.xml		http/samples/bridge/pom.xml
http/bridge/pom.xml		http/samples/cometd/pom.xml
http/bundle/pom.xml		http/samples/filter/pom.xml
http/cometd/pom.xml		http/samples/whiteboard/pom.xml
http/jetty/pom.xml		http/sslfilter/pom.xml
http/parent/pom.xml		http/whiteboard/pom.xml
http/pom.xml

Find all POMs in felix/http that are using SNAPSHOT versions

/Users/MikePigg/src/felix% grep SNAPSHOT http/**/pom.xml
http/api/pom.xml:        1-SNAPSHOT
http/api/pom.xml:    2.2.1-SNAPSHOT
http/base/pom.xml:        1-SNAPSHOT
http/base/pom.xml:    2.2.1-SNAPSHOT
http/bridge/pom.xml:        1-SNAPSHOT
http/bridge/pom.xml:    2.2.1-SNAPSHOT
                        .
                        .
                        .
http/samples/bridge/pom.xml:    2.2.1-SNAPSHOT
http/samples/cometd/pom.xml:        1-SNAPSHOT
http/samples/cometd/pom.xml:    2.2.1-SNAPSHOT
http/samples/filter/pom.xml:        1-SNAPSHOT
http/samples/filter/pom.xml:    2.2.1-SNAPSHOT
http/samples/whiteboard/pom.xml:        1-SNAPSHOT
http/samples/whiteboard/pom.xml:    2.2.1-SNAPSHOT
http/sslfilter/pom.xml:    0.0.1-SNAPSHOT
http/whiteboard/pom.xml:        1-SNAPSHOT
http/whiteboard/pom.xml:    2.2.1-SNAPSHOT

Command Autocorrect

When an entry looks like it might be a mistyped command, zsh will offer to correct it

enabled with 

setopt correct

Autocorrect for the save

/Users/MikePigg/src/felix/http% mnv compile
zsh: correct 'mnv' to 'mvn' [nyae]? y

Completion Features

zsh has rich support for completing

  • directory and file names
  • commands and executable files
  • arguments to commands

Customizing completion presentation

zstyle ":completion:*:descriptions" format "%B%d%b"
zstyle ':completion:*' group-name ''

Show me a description of each type of completion

Keep commands with their type

Showing completion descriptions and groups

Menu Selection

On second completion request goes into an interactive menu mode

Arrow keys can be used to select a completion

Enabled with 

zmodload zsh/complist
zstyle ':completion*:default' menu 'select=0'

Command completions

zsh has extensive support for completing command parameters in many programs

zsh-completions provides support for more external programs such as Maven

Basic Maven completion

% mvn <tab>
phase
clean             -- remove all files generated by the previous build
compile           -- compile the source code of the project
deploy            -- done in an integration or release environment, copies the
install           -- install the package into the local repository, for use as
integration-test  -- process and deploy the package if necessary into an enviro
package           -- take the compiled code and package it in its distributable
site              -- generates the projects site documentation
site-deploy       -- deploys the generated site documentation to the specified
test              -- run tests using a suitable unit testing framework
verify            -- run any checks to verify the package is valid and meets qu
                    
                        
Filling in Maven projects for pl parameter

% mvn compile -pl http<tab>
project
http                     http/jetty               http/samples/whiteboard
http/api                 http/parent              http/sslfilter
http/base                http/proxy               http/whiteboard
http/bridge              http/samples/bridge      httplite
http/bundle              http/samples/cometd      httplite/complete
http/cometd              http/samples/filter      httplite/core

Using completions for other commands

suppose we create a script called mvnbuild that has 

mvn clean install $@

Now we've lost command completion for maven - all we get is file completion

It would be nice to use the command completion for mvn with this command

compdef lets us tell the completion system what completion function to use for mvnbuild

% compdef _mvn mvnbuild
% mvnbuild -pl http
project
http                     http/jetty               http/samples/whiteboard
http/api                 http/parent              http/sslfilter
http/base                http/proxy               http/whiteboard
http/bridge              http/samples/bridge      httplite
http/bundle              http/samples/cometd      httplite/complete
http/cometd              http/samples/filter      httplite/core

Completing OS X Applications

Using the open command to open test.txt

open test.txt

By default, it will open in TextEdit

% open test.txt -a Ma<tab>
Mac OS X application
MacVim             MakePDF            ManagedClient      Match
Mail               MallocDebug        MassStorageCamera

Completing Branch Name for git

Felix has long branch names with pattern 'org.apache.felix.*'

felix% git checkout o<tab>rg.apache.felix.<tab>
org.apache.felix.framework-1.2.1
org.apache.felix.framework-1.8.0
org.apache.felix.framework-1.8.1-RC
org.apache.felix.framework-2.0.5-RC
org.apache.felix.framework-3.0.8-RC
org.apache.felix.framework-4.0.3-RC
org.apache.felix.main-1.2.1
org.apache.felix.main-1.8.0
org.apache.felix.main-1.8.1-RC
org.apache.felix.main-2.0.5-RC
org.apache.felix.main-3.0.8-RC
org.apache.felix.main-4.0.3-RC
org.apache.felix.main.distribution-2.0.5-RC
org.apache.felix.main.distribution-3.0.8-RC
org.apache.felix.main.distribution-4.0.3-RC

Creating Custom Completions

Suppose I need to clone git repos from

  • Github
  • A private git server

I'd like to not have to type out the common URL each time (https://github.com/)

One way to address this is to set up a completion function for git clone

Step One

Create a shell function shortcut

shorter

won't have collisions with existing git completion

gcl () {
	git clone "$@"
}

Step Two

Define a completion function for gcl in a file called _gcl

must be on fpath

#compdef gcl

_arguments ":clone repo:(${GCL_URLS})"

Step Three

Add urls

GCL_URLS=(https://github.com/ https://bitbucket.org/)

Step Four

Use it!

src % gcl <tab>
                
src % gcl https://<tab>
clone repo
https://bitbucket.org/  https://github.com/

VCS Info

vcs_info module

Supports git, svn, hg, etc.

Allows customizing command line with useful info

  • current branch
  • state indication (staged, unstaged, etc.)

Basic VCS info on left

%b in formats = current branch name

setopt prompt_subst
autoload -Uz vcs_info
zstyle ':vcs_info:*' enable git svn
zstyle ':vcs_info:*' formats '[%b]'
precmd() { vcs_info }
PROMPT='%c ${vcs_info_msg_0_}%# '

Basic VCS info on right

PROMPT='%c%# '
RPROMPT='${vcs_info_msg_0_}'

Add some color

%F = start foreground color

%f = end coloring

zstyle ':vcs_info:*' formats '%F{5}[%F{2}%b%F{5}]%f'

Add VCS state in git

Shows us when we have staged, unstaged, or untracked files in the repo

zstyle ':vcs_info:*' stagedstr 'M'
zstyle ':vcs_info:*' unstagedstr 'U'
zstyle ':vcs_info:*' check-for-changes true
zstyle ':vcs_info:git*+set-message:*' hooks git-untracked
+vi-git-untracked() {
    if [[ $(git rev-parse --is-inside-work-tree 2> /dev/null) == 'true' ]] && \
        git status --porcelain  | grep '??' &> /dev/null; then
        hook_com[unstaged]+='%F{1}??%f'
    fi
}
zstyle ':vcs_info:*' formats '%F{5}[%F{2}%b%F{5}] %F{2}%c%F{3}%u%f'
zstyle ':vcs_info:*' actionformats '%F{5}[%F{2}%b%F{3}|%F{1}%a%F{5}]%f'
Thanks Christopher!: http://stackoverflow.com/a/12935606/576077

untracked file

staged file

modified file

Themes

promptinit

$ autoload -U promptinit
$ promptinit
                 
~% prompt<tab>
prompt theme
adam1    bart     clint    elite2   fire     oliver   redhat   walters
adam2    bigfade  elite    fade     off      pws      suse     zefram

check 'em out

Configuring zsh

  • https://github.com/michaelpigg/dotfiles
  • https://github.com/holman/dotfiles
  • https://github.com/robbyrussell/oh-my-zsh

More Resources

  • Book: From Bash to Z Shell; Kiddle, et. al.
  • https://github.com/grml/zsh-lovers
  • http://zsh.sourceforge.net/

Thanks!

Michael Pigg

@mikepigg

@ChariotSolution

@techcast