diff --git a/bin/env.sh b/bin/env.sh
index b4d0d2bb8..51e8f1ca4 100644
--- a/bin/env.sh
+++ b/bin/env.sh
@@ -4,13 +4,13 @@ thisEnv=${BASH_SOURCE[0]:-$0}
 export CLAS12DIR=$(realpath $(dirname $thisEnv)/..)
 
 # Set default field maps (but do not override user's env):
-if [ -z "$COAT_MAGFIELD_TORUSMAP" ]; then
+if [ -z "${COAT_MAGFIELD_TORUSMAP-}" ]; then
     export COAT_MAGFIELD_TORUSMAP=Symm_torus_r2501_phi16_z251_24Apr2018.dat
 fi
-if [ -z "$COAT_MAGFIELD_TORUSSECONDARYMAP" ]; then
+if [ -z "${COAT_MAGFIELD_TORUSSECONDARYMAP-}" ]; then
     export COAT_MAGFIELD_TORUSSECONDARYMAP=Full_torus_r251_phi181_z251_25Jan2021.dat
 fi
-if [ -z "$COAT_MAGFIELD_SOLENOIDMAP" ]; then
+if [ -z "${COAT_MAGFIELD_SOLENOIDMAP-}" ]; then
     export COAT_MAGFIELD_SOLENOIDMAP=Symm_solenoid_r601_phi1_z1201_13June2018.dat
 fi
 
diff --git a/build-coatjava.sh b/build-coatjava.sh
index 9ba7ca377..c45468361 100755
--- a/build-coatjava.sh
+++ b/build-coatjava.sh
@@ -1,5 +1,9 @@
 #!/bin/bash
 
+set -e
+set -u
+set -o pipefail
+
 usage='build-coatjava.sh [-h] [--quiet] [--spotbugs] [--nomaps] [--unittests]'
 
 quiet="no"
@@ -25,7 +29,7 @@ do
         quiet="yes"
     else
         echo "$usage"
-        exit
+        exit 2
     fi
 done
 
@@ -77,7 +81,7 @@ if [ $downloadMaps == "yes" ]; then
         echo ERROR:::::::::::  Could not download field map:
         echo $webDir/$map
         echo One option is to download manually into etc/data/magfield and then run this build script with --nomaps
-        exit
+        exit 1
     fi
   done
   cd -