diff --git a/scripts/release/linux_x64/build.sh b/scripts/release/linux_x64/build.sh
index 3e5a0cb..0156276 100755
--- a/scripts/release/linux_x64/build.sh
+++ b/scripts/release/linux_x64/build.sh
@@ -7,7 +7,7 @@ cd "$(dirname "$0")"
 
 repo_root="$(cd ../../.. && pwd)"
 
-if [ "$2" ]; then
+if [ "${2:-}" ]; then
 	cpu_set="--cpuset-cpus $2"
 else
 	cpu_set=""
diff --git a/scripts/release/macos_aarch64/build.sh b/scripts/release/macos_aarch64/build.sh
index d802e81..103cd2f 100755
--- a/scripts/release/macos_aarch64/build.sh
+++ b/scripts/release/macos_aarch64/build.sh
@@ -7,7 +7,7 @@ cd "$(dirname "$0")"
 
 repo_root="$(cd ../../.. && pwd)"
 
-if [ "$2" ]; then
+if [ "${2:-}" ]; then
 	cpu_set="--cpuset-cpus $2"
 else
 	cpu_set=""
diff --git a/scripts/release/windows_x64/build.sh b/scripts/release/windows_x64/build.sh
index 8b2e5c1..a476df0 100755
--- a/scripts/release/windows_x64/build.sh
+++ b/scripts/release/windows_x64/build.sh
@@ -7,7 +7,7 @@ cd "$(dirname "$0")"
 
 repo_root="$(cd ../../.. && pwd)"
 
-if [ "$2" ]; then
+if [ "${2:-}" ]; then
 	cpu_set="--cpuset-cpus $2"
 else
 	cpu_set=""