--title zsh: Power Tools.  Because having all your fingers is overrated.
--author Paul L. Snyder <plsnyder@drexel.edu>
--date January 12, 2009

--newpage
--heading A non-partisan guide to shell selection

--newpage
--heading sh

* The original Bourne shell
* Written by Stephen Bourne for Version 7 Unix in 1977
* Usually, your '/bin/sh' is another shell running in compatibility mode

---
Why should I use it?
---
* You are writing a "portable" shell script
---
* Your life will still be hell
---
* If you're writing a large system, use a real programming lanugage (Perl, Python, etc.)

--newpage 
--heading ksh

* David Korn's Korn shell
* MUCH better for programming than sh or *shudder* csh
* Some interactive improvements
* Two major versions, ksh88 and ksh93 (finally open sourced in 2000)
* The FSF released pdksh (mostly ksh88-compatible)

---
Why should I use it?
---
* Misguided nostalgia

--newpage
--heading csh

* The "C" shell
* Ha!
* Introduced many now-standard interactive features (job control, aliases, !-substitution
* Nastily brain-damaged scripting behavior
* Csh Programming Considered Harmful: http://www.faqs.org/faqs/unix-faq/shell/csh-whynot/
* Implementations were historically very buggy
* The modern Hamilton C Shell fixes many of the problems.  But why?

---
Why should I use it?
---
* You are an idiot.

--newpage
--heading tcsh

* t is for 'TENEX'
* The TENEX OS (later TOPS-20) had command completion facilities
* tcsh introduced programmable command completion to Unix shells
* kept the csh syntax

---
Why should I use it?
---
* You like having cool people laugh at you.
---
* Actually, there is no good reason to use tcsh.

--newpage
--heading bash

* The Bourne-again shell
* ksh was proprietary and csh sucked, so bash was created
* Considered a ksh descendant
* Default shell for most Linux distributions
* /bin/sh is usually bash under the covers (except on Ubuntuish systems)

---
Why should I use it?
---
* You like the safety of being one of the herd
---
* Power scares you
---
* You are pathetically grateful for finally receiving features zsh has had for years

--newpage
--heading The Z shell

* Mostly descended from ksh
---
* Absorbs interesting (and possibly conflicting) features from other shells
---
* Possesses the lucid clarity of perl...
---
* ...and the streamlined elegance of emacs

---
Why should I use it?
---
* See remainder of presentation, below

--newpage shell usage 1
--heading Shell usage...

 * Scripting

   - Make common tasks easier
---

   - Use POSIX sh for portability, not zsh

     = Portable shell code is non-trivial

---
   - Don't write large systems using shell scripting!

     = Use, e.g., Perl, Python, Ruby
--newpage shell usage 2
--heading ...and Shell Usage
 * Interactive use

   - Make common tasks easier

---
   - Flexible command-line editing and history

---
   - Globbing

---
   - Completion

--newpage agenda
--heading Agenda

 * Startup files

 * zsh's modular design

 * Variables

 * Expansion and substitution

 * Interactive use

 * Completion
--newpage initial words
--heading But first, a few words...

 * zsh in all its gory glory is unspeakably complex
---

 * Happily, you don't need to know much to start using the shell
---

 * zsh rewards knowledge with power
--newpage startup
--heading Startup files

Login files are run in this order ($ZDOTDIR defaults to $HOME):

 /etc/zshenv        Run by all shells, cannot be overridden
 $ZDOTDIR/.zshenv   Run by all shells (if RCS option is set)
--- 
 /etc/zprofile      Run by login shells (if GLOBAL_RCS is set)
 $ZDOTDIR/.zprofile Run by login shells (if RCS is set)
---
 /etc/zshrc         Run by interactive shells (if GLOBAL_RCS)
 $ZDOTDIR/.zshrc    Run by interactive shells (if RCS is set)
---
 /etc/zlogin        Run by login shells (if GLOBAL_RCS is set)
 $ZDOTDIR/.zlogin   Run by login shells (if RCS is set)

--newpage shutdown
--heading Shutdown files

When exiting:

 $ZDOTDIR/.zlogout  Run by login shells (if RCS is set)
 /etc/zlogout       Run by login shells (if GLOBAL_RCS is set)

--newpage creating dotfiles
--heading How do you create your startup files?

 * zsh is pretty bland until it has been configured.
---
 * Most of the cool options are turned off by default.
---
 * Two courses:

---
   - Steal someone else' .zshrc

---
   - Use the menu-based zsh-newuser-install (many distributions
     configure this to be run by default) [demo]

--newpage zsh-newuser-install
--heading Running zsh-newuser-install

   - If this isn't the case you can run it yourself:

--beginshelloutput
$ autoload -Uz zsh-newuser-install; zsh-newuser-install -f
--endshelloutput

--newpage modules
--heading zsh Modules
 * Portions of the shell are compiled as optional .so modules.
   They can be loaded using 'zmodload'.  Modules include:
   - zsh/zftp: command-line FTP program
   - zsh/complete: Programmable completion system
   - zsh/net/socket: 'zsocket' command to maniplate UNIX
       domain sockets
   - zsh/net/tcp: 'ztcp' command to create and accept TCP
       connections
   - zsh/zpty: Run a command under its own pseudo-terminal

--newpage modules2
--heading more zsh Modules
 * A few more modules of interest:
   - zsh/termcap and zsh/terminfo: output termcap and terminfo
       sequences by capability name
   - zsh/mapfile: tie a file to an associative array
   - zsh/newuser: menu-drive dot-file creation for new users
   - zsh/pcre and zsh/regex: Perl-compatible and POSIX regexes

--newpage arrays
--heading Arrays

--beginshelloutput
  $ beer=('Hop Devil' 'Golden Monkey' 'Old Horizontal')
  $ print $beer[2]   # or ${beer[2]}
  Golden Monkey
  $ print $foo[-1]   # negative subscripts allowed
  Old Horizontal
--endshelloutput
 
---
  * 'setopt ksharrays' for ksh-style behavior
---
  * bash 3 supports arrays of this type

--newpage hashes
--heading Associative Arrays!

--beginshelloutput
  $ typeset -A collective
  $ collective=(larks exaltation ravens unkindness crows murder)
  $ print $collective[larks]
  exaltation
  $ print ${(k)collective}
  larks ravens crows

---
  * You may be familiar with these as perl hashes
---
  * Associative array support will be coming in bash 4

--newpage numeric variables
--heading Typed numeric variables

  * Integers:                           typeset -i foo
  * Alternate base integers:            typeset -i 16 bar
  * Floating point, fixed notation:     typeset -F baz
  * Floating point, scientific notation:typeset -E womble

--beginshelloutput
$ zmodload zsh/mathfunc
$ (( pi = 4.0 * atan(1.0) ))
$ echo $pi
3.1415926536
--endshelloutput

--newpage typset tricks
--heading Fun with typeset

 * Create a tied variable/array pair: typeset -T FOO foo

 * Create a variable that always expands to lowercase: typeset -l BAR

 * Or uppercase: typeset -u BAZ

 * Make a variable read-only: typeset -r WOMBLE

 * Keep array entries unique: typeset -U path
--newpage prompts
--heading Prompts
  * PS1 displayed at regular command prompt

  * PS2 for second-level prompt

    - Also displays details of nested shell constructs [demo]

  * PS3 displayed inside 'select' construct'
  
  * PS4 is the trace prompt
---

  * RPS1 and RPS2 are right prompts!  'RPS1=%t'

--newpage prompt expansion
--heading Prompt expansion (a partial list)
  
  %M  FQ hostname            %#  '#' if shell is privileged, '%' otherwise
  %m  hostname up to '.'     %_  nesting status of shell constructs (for PS2)
  %n  username               %d  Present working directory - $PWD
  %y  User's login tty       %3d Last three components of $PWD
  %h  Current history num    %i  Line number of a trace (for PS4)
  %n  Current script or func %D  Date in yy-mm-dd   %t time in 12-hour format
  %{..%} Escape sequence     %D{format} format date using strftime(3)
  %n(x.true-text.false-text)  E.g. %# = $(!.#.$)

  ! privileges  # effective uid is n  ? exit status of last command is n
  d day of the month is n  / current absolute path has n elements
 
--newpage expansion
--heading Expansion and Substitution

When you enter a command at the prompt, it is mangled as follows:

  1. History Expansion
  2. Alias Expansion
  3. Process Substitution, 
     Parameter Expansion,
     Command Substitution,
     Arithmetic Substitution, and
     Brace Expansion
  4. Filename Expansion
  5. Filename Generation ("globbing")

--newpage history
--heading History

 * History is inspired by csh's history system
---
   - setopt CSH_JUNKIE_HISTORY to lobotomize zsh
---

 !! is the last command executed
---
 !!$ is the last word of the last command
---
 !n refers to history command numbered 'n'
---
 'history' for a list, or add '%h' to your prompt
---
 !str last command starting with 'str'
---
 !# is the command you are typing right now!
---
 !?str[?] is the last command containing 'str'
---
 !{...} prevents confusion with surrounding text

--newpage word selectors
--heading Selecting a word in a history line

 0   the first word
 n   the nth argument
 ^   the first argument
 $   the last argument
 %   the word match by a 'str' search
 n-m words n through m
 *   all the arguments

--newpage modifiers
--heading History modifiers
 
For extra fun, use these with regular parameters!

 h     remove one trailing path component
 t     remove all but the last path component
 r     remove filename extension
 e     remove everything but the extension
 l     convert all words to lowercase
 u     convert all words to uppercase
---

[g]s/old/new[/] Replace 'old' string with 'new'.
       if 'new' contains '&', '&' is replaced with 'old'
--newpage modified modifiers
--heading ...and Modifing the Modifiers!

 f       repeat following modifier exhaustively
 F:expr: repeat following modifier expr times 
 w       apply following modifier to each word
 W:sep:  like w, but applies to parts of string
           that are separated by 'sep'
--newpage parameter expansion
--heading Parameter expansion
 * All the usual suspects. E.g.:
--beginshelloutput
 $ echo ${foo?BAR}
 BAR
 $ foo=FOO
 $ echo ${foo?BAR}
 FOO
 $ baz=/this/is/a/path
 $ echo ${baz%is*}
 /this/
 $ echo ${baz/*is}
 /a/path
--endshelloutput

--newpage flags
--heading Change things up with parameter expansion flags

 There are LOTS of these...this is just a small selection
 Place in parentheses before the parameter name, e.g., ${(%)PS1}

  %  Expand prompt sequences
  C  Capitalize each resulting word
  L  Convert all letters to lowercase
  o  sort words in ascending order
  O  sort words in descending order
  u  expand only first unique occurence
      of each word
  j:str: join the words of arrays using 'str'
  q  quote the expanded words

--newpage globbing
--heading Filename generation, a.k.a. globbing

  - You all know about *, ?, [x] and [^y].
---

  - How about 'ls bar<2-6>'?  Only matches existing files
---

  - ^*FOO* globs all files without 'FOO' in their names
---

  - *(foo|bar)* globs files with either 'foo' or 'bar'
---

  - ba^z* globs 'bar' but not 'baz'
---

  - (foo)# matches zero or more 'foo's...(foo)## matches any number
--newpage ksh globbing
--heading It gets worse...

 - Use ksh-style glob operators to tweak your parentheses
---ls

 - *(foo) matches zero or more 'foo's
---

 - ?(foo) matches zero or one 'foo's
---

 - +(foo) matches one of more 'foo's
---

 - !(foo) match anything BUT 'foo'

---
 - Are you frightened yet?
--newpage globbing flags
--heading We're not done...it's time for globbing flags!


---
 - (#l) lowercase characters match upper or lower case; uppercase matches
        uppercase  (#I) reenables case sensitivity
---

 - (#b) activate backreferences for parenthesized groups; store the
        matches in the $match array and the indices in $mbegin and $mend
	(#B) ends backreferencing.
---

 - (#aN) Use approximate matching! Allow up to N errors in the match.
---
 
--newpage glob qualifiers
--heading Ye gods, there's more!

 Glob qualifiers appear in parentheses at the end of a glob specifier...
---
 *(.) matches regular files only
---
 *(/) matches all directories
---
 *(@) matches all symbolic links
---
 *(x) matches all owner-executable files
---
 *(s) matches all setuid files
---
 *(f{go+w}) matches group or other-writeable files!
---
This next one even scares me...
---
 *(estring) executes string as shell code!  The
   currently matched file is available in $REPLY;
   override the return with $reply or $REPLY.  Yipes!
--newpage recursive globbing
--heading Recursive Globbing

  One last trick...

    $ ls **/foo*
---

  Matches 'foo*' current directory or any subdirectory!

--newpage simple structures
--heading ...And now for something completely simple

      for x in *; do mv $x ${x:r}.bak; done

---
  Too much work!  In zsh, just use

      for x in *; mv $x ${x:r}.bak
---

  Actually, this is now deprecated, so it's a bad
  habit that I keep using it.

---
  Similar short forms exist for 'if', 'while', and so on.

---
  Even better better:
  
      zmv '(file0?)' '$1.bak'

--newpage zmv
--heading zmv

 * zmv is the command-line rename tool you've always wanted

--beginshelloutput
 $ zmv '(*)-(*).mpeg3' '$2_$1.mp3'
---
 $ zmv '(*)' '${(L)1}'
---
 $ alias mmv='noglob zmv -W'
 $ mmv *.pl.bak backups/*.pl
--endshelloutput

--newpage correction
--heading Correction
  * Oopsing commands?  'setopt CORRECT'

---
  * Fat-fingering filenames?  'setopt CORRECT_ALL'

---
  * Prevent a command from being corrected: alias mv='nocorrect mv'

--newpage multios
--heading MULTIOS and redirection

 setopt MULTIOS for built-in tee functionality

   $ ls >>file1 >file2 | cat
---

   $ : > *

 This truncates every file matched by *!
 
---
 Well, not quite, as long as NO_CLOBBER is set.  For maximum damage, use

   $ : >| *
--newpage more multios
--heading More MULTIOS

 How about a NULLCMD?

   $ <first <second >combined
---

 Change the default command by setting NULLCMD to something other than 'cat'
---

  $ >combined
---
  zsh: file exists: combined

  NOCLOBBER saves your bacon.
--newpage interactive
--heading Useful interactive features
  * Multi-line editing

---
  * Variable editing!  'vared path'

---
  * 'zed' is zsh's built-in editor...use your zsh bindings for a quick edit
    (use C-j to save and exit or C-g to cancel)
---
  
  * One of my favorites: the buffer stack

    $ bindkey '\eq' push-line-or-edit
 
  * Stuff the buffer with 'print -z'
--newpage completion
--heading Finally, completion
 * I'm not going to tell you how to write new completion functions

---
 * I don't want to be lynched. 

---

 * Besides, most anything you'd want to complete is probably in
   there already.

---
 * To get started using completion, just turn it on when you run zsh-newuser-install

--newpage education through completion
--heading Education through Completion
 * Forgot an option?  Just hit TAB

 * Look at completions for 'tar', 'mplayer', 'emerge', or 'dpkg'
--newpage information
--heading Bedtime reading

  * man zsh and its 15 subpages (or just man zshall)

  * http://www.zsh.org

    - Read the zsh user manual...friendly and useful

  * Tips and tricks

    - http://www.rayninfo.co.uk/tips/zshtips.html
    - http://gd.tuwien.ac.at/opsys/linux/grml/grml-www/zsh/zsh-lovers.html
     
  * http://www.zshwiki.org
--newpage end
--heading Fin.

--newpage random file
--heading Selecting a random file from the current directory

--beginshelloutput
 $ files=(*); echo $files[$RANDOM%$#files]]
--endshelloutput

--newpage suffix aliases
--heading For the brain-damaged by Windows: file associations

--beginshelloutput
 $ alias -s txt=less
--endshelloutput
---

  This can be bad for security!
--newpage global aliases
--heading Global aliases work anywhere in the line

--beginshelloutput
 $ alias -g ...='../..'
 $ alias -g L='| less'
 $ alias -g G='| egrep'
--endshelloutput

--newpage named directories
--heading Name your favorite directories with CDABLE_VARS

--newpage auto_cd
--heading Eschew cd with AUTO_CD and AUTO_PUSHD

--newpage