diff --git a/completions/bash/brew b/completions/bash/brew
index d7197267f9..5d79136756 100644
--- a/completions/bash/brew
+++ b/completions/bash/brew
@@ -1,6 +1,6 @@
 # Bash completion script for brew(1)
 
-if test -v POSIXLY_CORRECT || test -o posix 
+if [[ -n ${POSIXLY_CORRECT} ]] || shopt -oq posix
 then
   echo "Homebrew Bash completions do not work in POSIX mode" 1>&2
   return