diff --git a/build/builtin-actors/fetch-bundles.sh b/build/builtin-actors/fetch-bundles.sh
index e36bd84bb..37b8e906e 100755
--- a/build/builtin-actors/fetch-bundles.sh
+++ b/build/builtin-actors/fetch-bundles.sh
@@ -1,7 +1,7 @@
 #!/bin/bash
 set -e
 
-cd $(dirname "$0")
+cd "$(dirname "$0")"
 
 # gateway to use
 dweb="dweb.link"
@@ -20,7 +20,7 @@ check() {
     file=$1
     hash=$2
     if [ -e "$file" ]; then
-        echo "$hash $file" | sha256sum --check
+        echo "$hash  $file" | shasum -a 256 --check
     else
         return 1
     fi
@@ -30,22 +30,22 @@ fetch() {
     output=$1
     cid=$2
     hash=$3
-    if (check $output $hash); then
+    if (check "$output" "$hash"); then
         return 0
     else
         echo "fetching $cid to $output"
-        curl -k "https://$dweb/ipfs/$cid" -o $output
-        check $output $hash || die "hash mismatch"
+        curl -k "https://$dweb/ipfs/$cid" -o "$output"
+        check "$output" "$hash" || die "hash mismatch"
     fi
 }
 
-if [ ! -z "$actors7_cid" ]; then
+if [ -n "$actors7_cid" ]; then
     fetch builtin-actors-v7.car "$actors7_cid" "$actors7_hash"
 else
     touch builtin-actors-v7.car
 fi
 
-if [ ! -z "$actors8_cid" ]; then
+if [ -n "$actors8_cid" ]; then
     fetch builtin-actors-v8.car "$actors8_cid" "$actors8_hash"
 else
     touch builtin-actors-v8.car