diff --git a/lib/functions.zsh b/lib/functions.zsh
index 63ab755cf..c0ad78a5f 100644
--- a/lib/functions.zsh
+++ b/lib/functions.zsh
@@ -3,11 +3,11 @@ function zsh_stats() {
 }
 
 function uninstall_oh_my_zsh() {
-  /usr/bin/env ZSH=$ZSH /bin/sh $ZSH/tools/uninstall.sh
+  /usr/bin/env ZSH=$ZSH bash $ZSH/tools/uninstall.sh
 }
 
 function upgrade_oh_my_zsh() {
-  /usr/bin/env ZSH=$ZSH /bin/sh $ZSH/tools/upgrade.sh
+  /usr/bin/env ZSH=$ZSH bash $ZSH/tools/upgrade.sh
 }
 
 function take() {
diff --git a/tools/check_for_upgrade.sh b/tools/check_for_upgrade.sh
index 581f03a07..73e5e2384 100644
--- a/tools/check_for_upgrade.sh
+++ b/tools/check_for_upgrade.sh
@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 
 function _current_epoch() {
   echo $(($(date +%s) / 60 / 60 / 24))
@@ -9,7 +9,7 @@ function _update_zsh_update() {
 }
 
 function _upgrade_zsh() {
-  /usr/bin/env ZSH=$ZSH /bin/sh $ZSH/tools/upgrade.sh
+  /usr/bin/env ZSH=$ZSH bash $ZSH/tools/upgrade.sh
   # update the zsh file
   _update_zsh_update
 }