diff --git a/apt-dater-history-prune b/apt-dater-history-prune
index e1013df..fb11bfc 100755
--- a/apt-dater-history-prune
+++ b/apt-dater-history-prune
@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 # Prune old apt-dater history
 MTIME=+365
 
diff --git a/dir-empty b/dir-empty
index b57cf5b..fb96649 100755
--- a/dir-empty
+++ b/dir-empty
@@ -2,7 +2,7 @@
 # Check that all of the given directories are empty
 
 for d in "$@"; do
-  if [[ -n "$(ls -1 "$d")" ]]; then
+  if [ -n "$(ls -1 "$d")" ]; then
     exit 1
   fi
 done
diff --git a/randint b/randint
index 7eba0f2..ab95870 100755
--- a/randint
+++ b/randint
@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 # Give a random integer between 1 and $1 inclusive
 
 min=1