Merge pull request #1327 from agnoster/master

BY POPULAR DEMAND... the "agnoster" theme... 

themes/agnoster.zsh-theme

+# vim:ft=zsh ts=2 sw=2 sts=2
+#
+# agnoster's Theme - https://gist.github.com/3712874
+# A Powerline-inspired theme for ZSH
+#
+# # README
+#
+# In order for this theme to render correctly, you will need a
+# [Powerline-patched font](https://gist.github.com/1595572).
+#
+# In addition, I recommend the
+# [Solarized theme](https://github.com/altercation/solarized/) and, if you're
+# using it on Mac OS X, [iTerm 2](http://www.iterm2.com/) over Terminal.app -
+# it has significantly better color fidelity.
+#
+# # Goals
+#
+# The aim of this theme is to only show you *relevant* information. Like most
+# prompts, it will only show git information when in a git working directory.
+# However, it goes a step further: everything from the current user and
+# hostname to whether the last call exited with an error to whether background
+# jobs are running in this shell will all be displayed automatically when
+# appropriate.
+
+### Segment drawing
+# A few utility functions to make it easy and re-usable to draw segmented prompts
+
+CURRENT_BG='NONE'
+SEGMENT_SEPARATOR='⮀'
+
+# Begin a segment
+# Takes two arguments, background and foreground. Both can be omitted,
+# rendering default background/foreground.
+prompt_segment() {
+  local bg fg
+  [[ -n $1 ]] && bg="%K{$1}" || bg="%k"
+  [[ -n $2 ]] && fg="%F{$2}" || fg="%f"
+  if [[ $CURRENT_BG != 'NONE' && $1 != $CURRENT_BG ]]; then
+    echo -n " %{$bg%F{$CURRENT_BG}%}$SEGMENT_SEPARATOR%{$fg%} "
+  else
+    echo -n "%{$bg%}%{$fg%} "
+  fi
+  CURRENT_BG=$1
+  [[ -n $3 ]] && echo -n $3
+}
+
+# End the prompt, closing any open segments
+prompt_end() {
+  if [[ -n $CURRENT_BG ]]; then
+    echo -n " %{%k%F{$CURRENT_BG}%}$SEGMENT_SEPARATOR"
+  else
+    echo -n "%{%k%}"
+  fi
+  echo -n "%{%f%}"
+  CURRENT_BG=''
+}
+
+### Prompt components
+# Each component will draw itself, and hide itself if no information needs to be shown
+
+# Context: user@hostname (who am I and where am I)
+prompt_context() {
+  local user=`whoami`
+
+  if [[ "$user" != "$DEFAULT_USER" || -n "$SSH_CLIENT" ]]; then
+    prompt_segment black default "%(!.%{%F{yellow}%}.)$user@%m"
+  fi
+}
+
+# Git: branch/detached head, dirty status
+prompt_git() {
+  local ref dirty
+  if $(git rev-parse --is-inside-work-tree >/dev/null 2>&1); then
+    ZSH_THEME_GIT_PROMPT_DIRTY='±'
+    dirty=$(parse_git_dirty)
+    ref=$(git symbolic-ref HEAD 2> /dev/null) || ref="➦ $(git show-ref --head -s --abbrev |head -n1 2> /dev/null)"
+    if [[ -n $dirty ]]; then
+      prompt_segment yellow black
+    else
+      prompt_segment green black
+    fi
+    echo -n "${ref/refs\/heads\//⭠ }$dirty"
+  fi
+}
+
+# Dir: current working directory
+prompt_dir() {
+  prompt_segment blue black '%~'
+}
+
+# Status:
+# - was there an error
+# - am I root
+# - are there background jobs?
+prompt_status() {
+  local symbols
+  symbols=()
+  [[ $RETVAL -ne 0 ]] && symbols+="%{%F{red}%}✘"
+  [[ $UID -eq 0 ]] && symbols+="%{%F{yellow}%}⚡"
+  [[ $(jobs -l | wc -l) -gt 0 ]] && symbols+="%{%F{cyan}%}⚙"
+
+  [[ -n "$symbols" ]] && prompt_segment black default "$symbols"
+}
+
+## Main prompt
+build_prompt() {
+  RETVAL=$?
+  prompt_status
+  prompt_context
+  prompt_dir
+  prompt_git
+  prompt_end
+}
+
+PROMPT='%{%f%b%k%}$(build_prompt) '