diff --git a/RELEASING b/RELEASING
index a116a8169..adc429224 100644
--- a/RELEASING
+++ b/RELEASING
@@ -42,7 +42,7 @@ Here are the steps to follow to create a new cairo release:
 	the following command will show each patch that has changed a
 	public header file since the given version:
 
-		find src/ -name '*.h' -not -name '*-private.h' -not -name '*-test.h' -not -name 'cairoint.h' | \
+		find src/ -name '*.h' ! -name '*-private.h' ! -name '*-test.h' ! -name 'cairoint.h' | \
 		xargs git log -p X.Y.Z.. --
 
 4) Increment cairo_version_{minor|micro} and LT_{CURRENT|VERSION|AGE}
diff --git a/src/check-headers.sh b/src/check-headers.sh
index 91a52a015..1d0ebf816 100755
--- a/src/check-headers.sh
+++ b/src/check-headers.sh
@@ -7,7 +7,7 @@ status=0
 
 echo Checking public headers for missing cairo_public decorators
 
-find "$srcdir" -name '*.h' -not -name '*-private.h' -not -name '*-test.h' -not -name 'cairoint.h' |
+find "$srcdir" -name '*.h' ! -name '*-private.h' ! -name '*-test.h' ! -name 'cairoint.h' |
 xargs grep -B 1 '^cairo_.*[ 	]\+(' |
 awk '
 /^--$/ { context=""; public=0; next; }