diff --git a/tools/rapids-download-from-s3 b/tools/rapids-download-from-s3
index ab69830..8eb8abf 100755
--- a/tools/rapids-download-from-s3
+++ b/tools/rapids-download-from-s3
@@ -7,7 +7,7 @@
 set -euo pipefail
 export RAPIDS_SCRIPT_NAME="rapids-download-from-s3"
 
-if [ -z "$1" ] || [ -z "$2" ]; then
+if [ -z "${1:-}" ] || [ -z "${2:-}" ]; then
   rapids-echo-stderr "Must specify input arguments: PKG_NAME and UNTAR_DEST"
   exit 1
 fi
diff --git a/tools/rapids-extract-conda-files b/tools/rapids-extract-conda-files
index e33f047..2c75c76 100755
--- a/tools/rapids-extract-conda-files
+++ b/tools/rapids-extract-conda-files
@@ -3,7 +3,7 @@
 set -eo pipefail
 export RAPIDS_SCRIPT_NAME="rapids-extract-conda-files"
 
-if [ -z "$1" ]; then
+if [ -z "${1:-}" ]; then
   rapids-echo-stderr "Must specify input argument: CONDA_PKG_DIR"
   exit 1
 fi
diff --git a/tools/rapids-package-name b/tools/rapids-package-name
index 945f2d0..dcbc9d5 100755
--- a/tools/rapids-package-name
+++ b/tools/rapids-package-name
@@ -7,7 +7,7 @@ export RAPIDS_SCRIPT_NAME="rapids-package-name"
 
 repo_name="${RAPIDS_REPOSITORY##*/}"
 
-if [ -z "$1" ]; then
+if [ -z "${1:-}" ]; then
   rapids-echo-stderr "Must specify input arguments: PKG_TYPE"
   exit 1
 fi
diff --git a/tools/rapids-pip-wheel-version b/tools/rapids-pip-wheel-version
index 197c4d2..3f38294 100755
--- a/tools/rapids-pip-wheel-version
+++ b/tools/rapids-pip-wheel-version
@@ -5,7 +5,7 @@
 set -exo pipefail
 export RAPIDS_SCRIPT_NAME="rapids-pip-wheel-version"
 
-if [ -z "$1" ]; then
+if [ -z "${1:-}" ]; then
   rapids-echo-stderr "Must specify input arguments: EPOCH_TIMESTAMP"
   exit 1
 fi
diff --git a/tools/rapids-upload-to-s3 b/tools/rapids-upload-to-s3
index f53db3c..89fba8f 100755
--- a/tools/rapids-upload-to-s3
+++ b/tools/rapids-upload-to-s3
@@ -7,7 +7,7 @@ set -eo pipefail
 source rapids-constants
 export RAPIDS_SCRIPT_NAME="rapids-upload-to-s3"
 
-if [ -z "$1" ] || [ -z "$2" ]; then
+if [ -z "${1:-}" ] || [ -z "${2:-}" ]; then
   rapids-echo-stderr "Must specify both input arguments: PACKAGE_NAME and PATH_TO_TAR_UP"
   exit 1
 fi
diff --git a/tools/rapids-wheel-ctk-name-gen b/tools/rapids-wheel-ctk-name-gen
index 7aedfe7..e74fddd 100755
--- a/tools/rapids-wheel-ctk-name-gen
+++ b/tools/rapids-wheel-ctk-name-gen
@@ -5,7 +5,7 @@
 #   1) ctk tag
 set -eu -o pipefail
 
-if [ -z "${1-}" ]; then
+if [ -z "${1:-}" ]; then
   rapids-echo-stderr "Must specify input argument: CTK_TAG"
   exit 1
 fi
diff --git a/tools/rapids-wheels-anaconda b/tools/rapids-wheels-anaconda
index 1d26c9a..8e36a66 100755
--- a/tools/rapids-wheels-anaconda
+++ b/tools/rapids-wheels-anaconda
@@ -15,7 +15,7 @@ set -eou pipefail
 source rapids-constants
 export RAPIDS_SCRIPT_NAME="rapids-wheels-anaconda"
 
-if [ -z "$1" ]; then
+if [ -z "${1:-}" ]; then
   rapids-echo-stderr "Must specify input arguments: WHEEL_NAME"
   exit 1
 fi
diff --git a/tools/rapids-wheels-anaconda-github b/tools/rapids-wheels-anaconda-github
index 163865a..0fdc2e3 100755
--- a/tools/rapids-wheels-anaconda-github
+++ b/tools/rapids-wheels-anaconda-github
@@ -14,8 +14,8 @@
 set -eou pipefail
 export RAPIDS_SCRIPT_NAME="rapids-wheels-anaconda-github"
 
-if [ -z "$1" ]; then
-  rapids-echo-stderr "Must specify input arguments: WHEEL_NAME"
+if [ -z "${1:-}" ] || [ -z "${2:-}" ]; then
+  rapids-echo-stderr "Must specify input arguments: WHEEL_NAME and PKG_TYPE"
   exit 1
 fi
 WHEEL_NAME="$1"