shell: have, path_(append|prepend|remove)

- have: command -v shorthand
- path_append: appends dir to PATH
- path_prepend: prepends dir to PATH
- path_remove: removes dir from PATH

scripts/install-z.sh

@@ -1,4 +1,9 @@
 #!/usr/bin/env bash
+#
+# Install z
+#
+# shellcheck source=shared.sh
+source "$HOME/.dotfiles/scripts/shared.sh"
 
 Z_GIT_PATH="https://github.com/rupa/z.git"
 Z_BIN_PATH="$XDG_BIN_HOME/z"
@@ -6,5 +11,5 @@ Z_BIN_PATH="$XDG_BIN_HOME/z"
 if [ ! -d "$Z_BIN_PATH" ]; then
   git clone "$Z_GIT_PATH" "$Z_BIN_PATH"
 else
-  echo "z ($Z_BIN_PATH/) already installed"
+  msg_done "z ($Z_BIN_PATH/) already installed"
 fi