diff --git a/themes/powerline/README.md b/themes/powerline/README.md
index 96108f1f..512461fb 100644
--- a/themes/powerline/README.md
+++ b/themes/powerline/README.md
@@ -5,7 +5,7 @@ A colorful theme, where shows a lot information about your shell session.
 **IMPORTANT:** This theme requires that [a font with the Powerline symbols](https://github.com/powerline/fonts) needs to be used in your terminal emulator, otherwise the prompt won't be displayed correctly, i.e. some of the additional icons and characters will be missing. Please follow your operating system's instructions to install one of the fonts from the above link and select it in your terminal emulator.
 
 **NOTICE:** The default behavior of this theme assumes that you have sudo privileges on your workstation. If it's not the case (i.e you are running on
-a corporate network) you can set the flag 'THEME_CHECK_SUDO=${THEME_CHECK_SUDO:=false}' in powerline.theme.bash
+a corporate network) you can set the flag 'THEME_CHECK_SUDO=false' in your ~/.bashrc or ~/.bash_profile
 
 ## Provided Information
 
diff --git a/themes/powerline/powerline.base.bash b/themes/powerline/powerline.base.bash
index a911d12b..ff039c7a 100644
--- a/themes/powerline/powerline.base.bash
+++ b/themes/powerline/powerline.base.bash
@@ -13,7 +13,7 @@ function __powerline_user_info_prompt {
   local user_info=""
   local color=${USER_INFO_THEME_PROMPT_COLOR}
 
-  if [[ "THEME_CHECK_SUDO" = true ]]; then
+  if [[ "${THEME_CHECK_SUDO}" = true ]]; then
     if sudo -n uptime 2>&1 | grep -q "load"; then
       color=${USER_INFO_THEME_PROMPT_COLOR_SUDO}
     fi