diff --git a/cime_config/testmods_dirs/allactive/mychem/shell_commands b/cime_config/testmods_dirs/allactive/mychem/shell_commands
new file mode 100644
index 00000000..d851f0e3
--- /dev/null
+++ b/cime_config/testmods_dirs/allactive/mychem/shell_commands
@@ -0,0 +1,8 @@
+rm -f $CIMEROOT/../components/cam/chem_proc/campp
+
+cp $CIMEROOT/../components/cam/src/chemistry/pp_trop_mam_oslo/chem_mech.in my_chem_mech.in
+sed -i 's/2.9/8.8/' my_chem_mech.in
+sed -i 's/BEGSIM/*BEGSIM/' my_chem_mech.in
+sed -i 's/ENDSIM/*ENDSIM/' my_chem_mech.in
+
+./xmlchange --append CAM_CONFIG_OPTS="--usr_mech_infile `pwd`/my_chem_mech.in"