diff --git a/Test/VeriFast/tasks/vTaskSwitchContext/preprocessing_scripts/prepare_file_for_VeriFast.sh b/Test/VeriFast/tasks/vTaskSwitchContext/preprocessing_scripts/prepare_file_for_VeriFast.sh
index 397d3f8e0..8cb4394ff 100755
--- a/Test/VeriFast/tasks/vTaskSwitchContext/preprocessing_scripts/prepare_file_for_VeriFast.sh
+++ b/Test/VeriFast/tasks/vTaskSwitchContext/preprocessing_scripts/prepare_file_for_VeriFast.sh
@@ -1,5 +1,4 @@
-#!/bin/zsh
-ps -o comm= -p $$
+#!/bin/bash
 
 # This script expects the following command line arguments:
 # $1 : Absolute path to the source file that should be prepared for VeriFast.
diff --git a/Test/VeriFast/tasks/vTaskSwitchContext/preprocessing_scripts/vf_rewrite.sh b/Test/VeriFast/tasks/vTaskSwitchContext/preprocessing_scripts/vf_rewrite.sh
index 40ee596c0..5c6191f6f 100755
--- a/Test/VeriFast/tasks/vTaskSwitchContext/preprocessing_scripts/vf_rewrite.sh
+++ b/Test/VeriFast/tasks/vTaskSwitchContext/preprocessing_scripts/vf_rewrite.sh
@@ -1,4 +1,4 @@
-ps -o comm= -p $$
+#!/bin/bash
 
 # This script rewrites a given source in-pace such that the result can be
 # processed by VeriFast. Each rewrite below concerns a specific construct