Added zsh improvements from work laptop and a doc

home_zsh/.zsh/functions/chpwd_update_git_vars

@@ -0,0 +1,4 @@
+# update the prompt after changing to a new directory. 
+# http://sebastiancelis.com/2009/11/16/zsh-prompt-git-users/
+
+update_current_git_vars

home_zsh/.zsh/functions/precmd_update_git_vars

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+if [ -n "$__EXECUTED_GIT_COMMAND" ]; then
+    update_current_git_vars
+    unset __EXECUTED_GIT_COMMAND
+fi
+

home_zsh/.zsh/functions/preexec_update_git_vars

@@ -0,0 +1,6 @@
+case "$1" in 
+    git*)
+    __EXECUTED_GIT_COMMAND=1
+    ;;
+esac
+

home_zsh/.zsh/functions/prompt_git_info

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+# Git prompt stuff
+# http://sebastiancelis.com/2009/11/16/zsh-prompt-git-users/
+
+if [ -n "$__CURRENT_GIT_BRANCH" ]; then
+    local s="("
+    s+="$__CURRENT_GIT_BRANCH"
+    case "$__CURRENT_GIT_BRANCH_STATUS" in
+        ahead)
+        git_color="%{${fg[yellow]}%}"
+        s+="↑"
+        ;;
+        diverged)
+        git_color="%{${fg[yellow]}%}"
+        s+="↕"
+        ;;
+        behind)
+        git_color="%{${fg[yellow]}%}"
+        s+="↓"
+        ;;
+    esac
+    if [ -n "$__CURRENT_GIT_BRANCH_IS_CLEAN" ]; then
+        git_color="%{${fg[green]}%}"
+    fi
+    if [ -n "$__CURRENT_GIT_BRANCH_IS_DIRTY" ]; then
+        git_color="%{${fg[red]}%}"
+        s+="⚡"
+    fi
+    s+=")"
+ 
+    printf " %s%s" "$git_color" $s
+fi
+

home_zsh/.zsh/functions/update_current_git_vars

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+#  This file is used to set a few environment variables which will make it easy to build up our prompt
+# http://sebastiancelis.com/2009/11/16/zsh-prompt-git-users/
+
+unset __CURRENT_GIT_BRANCH
+unset __CURRENT_GIT_BRANCH_STATUS
+unset __CURRENT_GIT_BRANCH_IS_DIRTY
+
+local st="$(git status 2>/dev/null)"
+
+if [[ -n "$st" ]]; then
+    local -a arr
+    arr=(${(f)st})
+    if [[ $arr[1] =~ 'Not currently on any branch.' ]]; then
+        __CURRENT_GIT_BRANCH='no-branch'
+    else
+        __CURRENT_GIT_BRANCH="${arr[1][(w)4]}";
+    fi
+
+    if [[ $st =~ 'nothing to commit, working directory clean' ]]; then
+        __CURRENT_GIT_BRANCH_IS_CLEAN='1'
+    fi
+
+    if [[ $arr[2] =~ 'Your branch is' ]]; then
+        if [[ $arr[2] =~ 'ahead' ]]; then
+            __CURRENT_GIT_BRANCH_STATUS='ahead'
+        elif [[ $arr[2] =~ 'diverged' ]]; then
+            __CURRENT_GIT_BRANCH_STATUS='diverged'
+        else
+            __CURRENT_GIT_BRANCH_STATUS='behind'
+        fi
+    fi
+
+    if [[ ! $st =~ 'nothing to commit' ]]; then
+        __CURRENT_GIT_BRANCH_IS_DIRTY='1'
+    fi
+
+fi