diff --git a/scripts/offlinepi/offlinepi-record b/scripts/offlinepi/offlinepi-record
index 0b1760122dc3..8f21a8eddca7 100755
--- a/scripts/offlinepi/offlinepi-record
+++ b/scripts/offlinepi/offlinepi-record
@@ -14,21 +14,21 @@ if [ -z "$path" ]; then
     exit 1
 fi
 
-if [ ! -z "$*" ]; then
+if [ -n "$*" ]; then
     echo "Unexpected extra arguments: $*"
     exit 1
 fi
 
 # Remove the file before starting
-rm $path 2> /dev/null
+rm "$path" 2> /dev/null
 
 # N.B. Additional options must be added _before_ the filter string
 exec mitmdump \
-    -w $path \
+    -w "$path" \
     --set stream_large_bodies=1000m \
     "~d pypi.org|files.pythonhosted.org|mitm.it"
 
 # stream_large_bodies: must be set to a large value or large responses will not be recorded
 #   resulting in an unexpected file endings during replays
 # ~d: only interactions with package index domains should be recorded
-#   we also allow `mitm.it` so healthchecks succeed when replaying
\ No newline at end of file
+#   we also allow `mitm.it` so healthchecks succeed when replaying
diff --git a/scripts/offlinepi/offlinepi-replay b/scripts/offlinepi/offlinepi-replay
index 36712d5d9214..fb7aa7dd4752 100755
--- a/scripts/offlinepi/offlinepi-replay
+++ b/scripts/offlinepi/offlinepi-replay
@@ -16,12 +16,12 @@ if [ -z "$path" ]; then
     exit 1
 fi
 
-if [ ! -z "$*" ]; then
+if [ -n "$*" ]; then
     echo "Unexpected extra arguments: $*"
     exit 1
 fi
 
-exec mitmdump --server-replay $path \
+exec mitmdump --server-replay "$path" \
     --server-replay-extra 500 \
     --set connection_strategy=lazy
 
diff --git a/scripts/offlinepi/offlinepi-stop b/scripts/offlinepi/offlinepi-stop
index e391742fba69..583903ab1eb2 100755
--- a/scripts/offlinepi/offlinepi-stop
+++ b/scripts/offlinepi/offlinepi-stop
@@ -14,11 +14,11 @@ if [ -z "$pid" ]; then
     exit 1
 fi
 
-if [ ! -z "$*" ]; then
+if [ -n "$*" ]; then
     echo "Unexpected extra arguments: $*"
     exit 1
 fi
 
-kill $pid 2> /dev/null
-wait $pid 2> /dev/null
+kill "$pid" 2> /dev/null
+wait "$pid" 2> /dev/null
 echo "Done!"
diff --git a/scripts/offlinepi/offlinepi-wait b/scripts/offlinepi/offlinepi-wait
index f54bab3e0537..5cfb87c91577 100755
--- a/scripts/offlinepi/offlinepi-wait
+++ b/scripts/offlinepi/offlinepi-wait
@@ -7,6 +7,7 @@
 #   offlinepi-wait-ready <pid>
 
 projectroot=$(realpath "$(dirname "$0")")
+healthcheck="$projectroot/offlinepi-healthcheck"
 
 pid=$1
 shift
@@ -16,15 +17,15 @@ if [ -z "$pid" ]; then
     exit 1
 fi
 
-if [ ! -z "$*" ]; then
+if [ -n "$*" ]; then
     echo "Unexpected extra arguments: $*"
     exit 1
 fi
 
 
 # Wait until the server is ready
-until $($projectroot/offlinepi-healthcheck); do
-    if ! kill -0 $pid 2> /dev/null; then
+until $healthcheck; do
+    if ! kill -0 "$pid" 2> /dev/null; then
         exit 1
     fi
     sleep 1