add the agnoster theme by agnoster ported to fish shell

themes/agnoster/fish_prompt.fish

+# agnoster's Theme - https://gist.github.com/3712874
+# A Powerline-inspired theme for FISH
+#
+# # README
+#
+# In order for this theme to render correctly, you will need a
+# [Powerline-patched font](https://gist.github.com/1595572).
+
+set -g CURRENT_BG NONE
+set SEGMENT_SEPARATOR \u2b80
+set RIGHT_SEGMENT_SEPARATOR \u2b80
+
+# ===========================
+# Helper methods
+# ===========================
+
+set -g __fish_git_prompt_showdirtystate 'yes'
+set -g __fish_git_prompt_char_dirtystate '±'
+set -g __fish_git_prompt_char_cleanstate ''
+
+function parse_git_dirty
+  set -l submodule_syntax
+  set submodule_syntax "--ignore-submodules=dirty"
+  set git_dirty (git status -s $submodule_syntax  2> /dev/null)
+  if [ -n "$git_dirty" ]
+    if [ $__fish_git_prompt_showdirtystate = "yes" ]
+      echo -n "$__fish_git_prompt_char_dirtystate"
+    end
+  else
+    if [ $__fish_git_prompt_showdirtystate = "yes" ]
+      echo -n "$__fish_git_prompt_char_cleanstate"
+    end
+  end
+end
+
+#set -g THEME_DISPLAY_USER yes
+# ===========================
+# Segments functions
+# ===========================
+
+function prompt_segment -d "Function to draw a segment"
+  set -l bg
+  set -l fg
+  if [ -n "$argv[1]" ]
+    set bg $argv[1]
+  else
+    set bg normal
+  end
+  if [ -n "$argv[2]" ]
+    set fg $argv[2]
+  else
+    set fg normal
+  end
+  if [ "$CURRENT_BG" != 'NONE' -a "$argv[1]" != "$CURRENT_BG" ]
+    set_color -b $bg
+    set_color $CURRENT_BG
+    #echo -n " %{$bg%F{$CURRENT_BG}%}$SEGMENT_SEPARATOR%{$fg%} "
+    echo -n "$SEGMENT_SEPARATOR "
+    set_color -b $bg
+    set_color $fg
+  else
+    set_color -b $bg
+    set_color $fg
+    echo -n " "
+  end
+  set CURRENT_BG $argv[1]
+  if [ -n "$argv[3]" ]
+    echo -n -s $argv[3] " "
+  end
+  #echo $CURRENT_BG $fg $bg
+end
+
+function prompt_finish -d "Close open segments"
+  if [ -n $CURRENT_BG ]
+    set_color -b normal
+    set_color $CURRENT_BG
+    #echo -n " %{%k%F{$CURRENT_BG}%}$SEGMENT_SEPARATOR"
+    echo -n "$SEGMENT_SEPARATOR "
+  end
+  set -g CURRENT_BG NONE
+end
+
+
+# ===========================
+# Theme components
+# ===========================
+
+function prompt_user -d "Display actual user if different from $DEFAULT_USER"
+  set USER_PROMPT (whoami)@(hostname)
+  if [ "$THEME_DISPLAY_USER" = "yes" ]
+    if [ "$user" != "$DEFAULT_USER" -o -n "$SSH_CLIENT" ]
+      prompt_segment black yellow $USER_PROMPT
+    end
+  end
+end
+
+function prompt_dir -d "Display the actual directory"
+  prompt_segment blue black (prompt_pwd)
+end
+
+
+
+function prompt_git -d "Display the actual git state"
+  set -l ref
+  set -l dirty
+  if git rev-parse --is-inside-work-tree >/dev/null 2>&1
+    set dirty (parse_git_dirty)
+    set ref (git symbolic-ref HEAD 2> /dev/null)
+    set ref (git symbolic-ref HEAD 2> /dev/null)
+    if [ $status -gt 0 ]
+      set -l branch (git show-ref --head -s --abbrev |head -n1 2> /dev/null)
+      set ref "➦ $branch "
+    end
+    set -l branch (echo $ref | sed  's-refs/heads/-⭠ -')
+    if [ "$dirty" != "" ]
+      prompt_segment yellow black "$branch $dirty"
+    else
+      prompt_segment green black "$branch $dirty"
+    end
+  end
+end
+
+function prompt_status -d "the symbols for a non zero exit status, root and background jobs"
+    if [ $RETVAL -ne 0 ]
+      prompt_segment black red "✘"
+    end
+
+    # if superuser (uid == 0)
+    set -l uid (id -u $user)
+    if [ $uid -eq 0 ]
+      prompt_segment black yellow "⚡"
+    end
+
+    # Jobs display
+    if [ (jobs -l | wc -l) -gt 0 ]
+      prompt_segment black cyan "⚙"
+    end
+end
+
+# ===========================
+# Apply theme
+# ===========================
+
+function fish_prompt
+  set -g RETVAL $status
+  prompt_status
+  prompt_user
+  prompt_dir
+  prompt_git
+  prompt_finish
+end
+