diff --git a/sapphire.sh b/sapphire.sh
index 368230b..12dbf96 100755
--- a/sapphire.sh
+++ b/sapphire.sh
@@ -1,3 +1,4 @@
+#!/usr/bin/env sh
 cd $(dirname $0)
 
 usage()
diff --git a/tools/build.sh b/tools/build.sh
index 51fef35..e1eb942 100755
--- a/tools/build.sh
+++ b/tools/build.sh
@@ -1 +1,2 @@
+#!/usr/bin/env sh
 cmake --build build --config "${1:-Debug}"
\ No newline at end of file
diff --git a/tools/format.sh b/tools/format.sh
index 1b5ded9..5efca64 100755
--- a/tools/format.sh
+++ b/tools/format.sh
@@ -1,3 +1,4 @@
+#!/usr/bin/env sh
 if [ ! -d build ]
 then
     mkdir build
diff --git a/tools/generate.sh b/tools/generate.sh
index 96ab6d7..892de70 100755
--- a/tools/generate.sh
+++ b/tools/generate.sh
@@ -1,3 +1,4 @@
+#!/usr/bin/env sh
 if [ ! -d build ]
 then
     mkdir build
diff --git a/tools/generateASTNode.sh b/tools/generateASTNode.sh
index a8866ce..5b5230f 100755
--- a/tools/generateASTNode.sh
+++ b/tools/generateASTNode.sh
@@ -1,3 +1,4 @@
+#!/usr/bin/env sh
 cd "$(dirname $0)"/../src/AST
 
 if [ "$1" == "" ]; then
diff --git a/tools/install.sh b/tools/install.sh
index b147d08..6f92e84 100755
--- a/tools/install.sh
+++ b/tools/install.sh
@@ -1,6 +1,7 @@
+#!/usr/bin/env sh
 cd build
 
-if [ "$1" == "" ]
+if [ -z "$1" ]
 then
 cmake --install .
 else