More fixes for update

update

@@ -1,5 +1,16 @@
 #!/bin/bash
 
+# The whole script is wrapped in { ...; exit; } so bash parses all of it before
+# running anything. That way, replacing this file mid-run (e.g. by git pull and
+# the copy below) can't make the running copy read a mix of old and new text.
+{
+
+# Install a script atomically (copy to a temp file, then rename over the target)
+install_script() {
+    local tmp
+    tmp="$(mktemp "$2.XXXXXX")" && cp "$1" "$tmp" && chmod 755 "$tmp" && mv -f "$tmp" "$2"
+}
+
 # Print the logo
 print_logo() {
     cat << "EOF"
@@ -28,9 +39,8 @@ if [[ -z "$UPDATE_REEXECED" ]] && ! git -C "$COREDESKTOP" pull; then
     export UPDATE_PULL_FAILED=1
 fi
 mkdir -p "$COREDESKTOP/updates.d"
-# --remove-destination replaces copies left root-owned by older versions of this script
-cp --remove-destination "$COREDESKTOP/update" ~/.local/bin/update
-cp --remove-destination "$COREDESKTOP/refresh" ~/.local/bin/refresh
+install_script "$COREDESKTOP/update" ~/.local/bin/update
+install_script "$COREDESKTOP/refresh" ~/.local/bin/refresh
 
 if [[ -z "$UPDATE_REEXECED" ]]; then
     export UPDATE_REEXECED=1
@@ -63,3 +73,5 @@ if (( ${#FAILED[@]} > 0 )); then
 fi
 
 echo "Done."
+exit 0
+}