diff --git a/scripts/build.sh b/scripts/build.sh
old mode 100644
new mode 100755
index 803dcdd..773f7ab
--- a/scripts/build.sh
+++ b/scripts/build.sh
@@ -1,3 +1,5 @@
+#!/bin/sh
+
 cd "$(git rev-parse --show-toplevel)"
 
 CFLAGS="$CFLAGS -std=c11 -pedantic -Wall -Wextra"
diff --git a/scripts/entr.sh b/scripts/entr.sh
old mode 100644
new mode 100755
index 69d58ca..7161fe9
--- a/scripts/entr.sh
+++ b/scripts/entr.sh
@@ -1,3 +1,4 @@
+#!/bin/sh
 cd "$(git rev-parse --show-toplevel)"
 find . -not \( -path './.git' -prune \) -not \( -path './build' -prune \) \
-	| entr -s 'clear && sh scripts/build.sh && sh scripts/test.sh'
+	| entr -s 'clear && scripts/build.sh && scripts/test.sh'
diff --git a/scripts/format.sh b/scripts/format.sh
old mode 100644
new mode 100755
index 9124d63..68074cd
--- a/scripts/format.sh
+++ b/scripts/format.sh
@@ -1,3 +1,4 @@
+#!/bin/sh
 cd "$(git rev-parse --show-toplevel)"
 find . -not \( -path './.git' -prune \) \
 	 -not \( -path './build' -prune \) \
diff --git a/scripts/test.sh b/scripts/test.sh
old mode 100644
new mode 100755
index 014e2d0..4a1ac84
--- a/scripts/test.sh
+++ b/scripts/test.sh
@@ -1,3 +1,5 @@
+#!/bin/sh
+
 cd "$(git rev-parse --show-toplevel)"
 
 fails=0