why Z shell (zsh) iscooler than your shell (unless your shell is zsh) Brendon Rapp - Cave Lunch #1
Donald Knuth Professor Emeritusof Computer Science at Stanford Author of The Art of Computer Programming "Father of algorithmic analysis" Creator of TeX
In 1986, Knuthwas asked to write a guest feature for the "Programming Pearls" column in the Communications of the ACM journal. The task was to write a program that would: read a file of text, determine the n most frequently used words, and print out a sorted list of those words along with their frequencies.
Knuth produced asolution in Pascal that, when printed, was about 10 pages in length. It was well designed, thoroughly commented, and used a novel data structure for managing the word count list.
In response, DougMcIlroy wrote a shell script that produced the same output.
In response, DougMcIlroy wrote a shell script that produced the same output. McIlroy's script was six lines long.
Doug McIlroy's ShellScript tr -cs A-Za-z 'n' | tr A-Z a-z | sort | uniq -c | sort -rn | sed ${1}q
A brief historyof shells 1971: Thompson shell ● Ken Thompson, Bell Labs, first Unix shell ● interactive interpreter, not scripting environment 1977: Bourne shell ● scripting language ● Version 7 Unix, PDP-11 ● 1984: The UNIX Programming Environment, Kernighan & Pike ● The shell of commercial Unixes ○ System V, AIX, HP-UX, SCO, Solaris, SunOS ○ Still the default on some of these (that are still alive) ● /bin/sh ○ compatibility mode in modern shells ○ symlink or hard link to compatible shells in modern Unixes
A brief historyof shells 1978: C shell ● BSD Unix ● More "C-like" scripting syntax (kinda) ● Command history ● Aliasing ● tcsh - newer C shell, default on FreeBSD, and OS X systems 10.0-10.2 1983: Korn shell ● Bell Labs (AT&T) ● Proprietary until 2000 ● vi and emacs editing modes ● Lots of C shell features ● "middle road" between Bourne and C shell ● pdksh - default on OpenBSD
A brief historyof shells 1989: Bourne Again shell (bash) ● GNU, GPL ● first legitimate Free shell (/bin/sh compatible) ○ shells like ksh and csh became Free only much later on ● standard shell for Linux distros, Mac OS X 10.3+ ● TAB completion ● extended scripting syntax 1990: Z shell ● most closely resembles Korn shell ● /bin/bash compatibility, drop-in replacement for Bash ● "new" (despite being over 20 years old) ● awesome stuff I'll talk about next
... your Bashis old! (OS X 10.8.2... and many earlier OS X versions too)
OS X: GPLWasteland ● no GPLv3 on OS X ● OS X bash: final version released as GPLv2 ● Homebrew has latest Bash (but many use situation as an excuse to try zsh instead)
bash: git completion It'spossible to get completion for git (and many other commands) in Bash by installing bash-completion package, but the completion is still rudimentary compared to zsh: ● no cycling through options with repeated tabs ● no accompanying info with commands, just a list ● breaks to new prompt line on each tab instead of updating in-place There may be ways to improve that situation and bring it more in line with zsh, but with zsh, you get it basically out-of-the-box, with a single command in your .zshrc to enable completions.
zsh: path expansion (... the path is expanded in place, provided there is only one path matching that pattern)
zsh: path expansion (If there isn't only one distinct match for the pattern...)
zsh: path expansion (... then TAB begins cycling through the possibilities... )
zsh: path expansion (... until you get to the one you want, and hit the Right arrow to "select" it ... )
zsh: path expansion (... and then TAB resumes matching through the rest of the path)
zsh: aliases Global aliases- appear anywhere in command string alias -g gp='| grep -i' % ps ax gp ruby => ps ax | grep -i ruby
zsh: aliases Suffix aliases- "Open With..." alias -s rb=vim alias -s log="less -MN" alias -s html=chromium % user.rb => vim user.rb % development.log => less -MN development.log % index.html => chromium index.html
Other zsh bulletpoints ● Simple configuration style ● Shared history ○ simple & fast, requires some monkeying to replicate in bash ● Lots of additions for shell scripting ● Output redirection to multiple destinations And, apparently, plenty of other stuff deeper than I've gotten so far.