New update command

lib/helpers.bash

@@ -32,13 +32,14 @@ function reload_plugins() {
 bash-it ()
 {
     about 'bash-it help and maintenance'
-    param '1: verb [one of: help | show | enable | disable ]'
+    param '1: verb [one of: help | show | enable | disable | update ] '
     param '2: component type [one of: alias(es) | completion(s) | plugin(s) ]'
     param '3: specific component [optional]'
     example '$ bash-it show plugins'
     example '$ bash-it help aliases'
     example '$ bash-it enable plugin git [tmux]...'
     example '$ bash-it disable alias hg [tmux]...'
+    example '$ bash-it update'
     typeset verb=${1:-}
     shift
     typeset component=${1:-}
@@ -53,6 +54,8 @@ bash-it ()
              func=_disable-$component;;
          help)
              func=_help-$component;;
+         update)
+             func=_bash-it_update;;
          *)
              reference bash-it
              return;;
@@ -115,6 +118,27 @@ _bash-it-plugins ()
     _bash-it-describe "plugins" "a" "plugin" "Plugin"
 }
 
+_bash-it_update() {
+  _about 'updates Bash it'
+  _group 'lib'
+
+  cd "${$BASH_IT}"
+  git fetch &> /dev/null
+  local status="$(git rev-list master..origin/master 2> /dev/null)"
+  if [[ -n "${status}" ]]; then
+    git pull --rebase &> /dev/null
+    if [[ $? -eq 0 ]]; then
+      echo "Bash it successfully updated, enjoy!"
+      reload
+    else
+      echo "Error updating Bash it, please, check if your Bash it installation folder (${BASH_IT}) is clean."
+    fi
+  else
+    echo "Bash it is up to date, nothing to do!"
+  fi
+  cd - &> /dev/null
+}
+
 _bash-it-describe ()
 {
     _about 'summarizes available bash_it components'
@@ -355,6 +379,13 @@ _help-plugins()
     rm $grouplist 2> /dev/null
 }
 
+_help-update () {
+  _about 'help message for update command'
+  _group 'lib'
+
+  echo "Check for a new version of Bash it and update it."
+}
+
 all_groups ()
 {
     about 'displays all unique metadata groups'