diff --git a/exstage4.sh b/exstage4.sh
index 504a02b..7f6a831 100755
--- a/exstage4.sh
+++ b/exstage4.sh
@@ -97,7 +97,7 @@ fi
 
 archiveExt="${archiveFile##*.}"
 
-if [[ "${archiveFile%%.$archiveExt}" = *.tar ]]; then
+if [[ "${archiveFile%%.$archiveExt}" != *.tar ]]; then
 	echo "The stage file you are trying to unpack (\`$archiveFile\`) does not appear to be an archived TAR file"
 	echo "${archiveFile%%.$archiveExt}"
 	exit 1