diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index eeea980..27fbeb5 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -10,7 +10,7 @@ jobs:
   test:
     strategy:
       matrix:
-        platform: [ubuntu-latest, macos-latest, ubuntu-18.04]
+        platform: [ubuntu-20.04, ubuntu-18.04, macos-11, macos-10.15]
     runs-on: ${{ matrix.platform }}
     steps:
     - uses: actions/checkout@v2
diff --git a/README.md b/README.md
index 4fc5128..925afc8 100644
--- a/README.md
+++ b/README.md
@@ -23,7 +23,12 @@ Download the latest stable [release][release] for use on your desktop or server.
 
 ```shell
 brew install todo-txt
+
+# For macOS on x86 CPU 
 cp -n /usr/local/opt/todo-txt/todo.cfg ~/.todo.cfg
+
+# For macOS on arm CPU
+cp -n /opt/homebrew/opt/todo-txt/todo.cfg ~/.todo.cfg
 ```
 
 **Note**: The `-n` flag for `cp` makes sure you do not overwrite an existing file.
diff --git a/todo.sh b/todo.sh
index f128e67..eebf361 100755
--- a/todo.sh
+++ b/todo.sh
@@ -824,11 +824,6 @@ _addto() {
     fi
 }
 
-shellquote()
-{
-    typeset -r qq=\'; printf %s\\n "'${1//\'/${qq}\\${qq}${qq}}'";
-}
-
 filtercommand()
 {
     filter=${1:-}
@@ -843,13 +838,13 @@ filtercommand()
         then
             ## First character isn't a dash: hide lines that don't match
             ## this $search_term
-            filter="${filter:-}${filter:+ | }grep -i $(shellquote "$search_term")"
+            printf -v filter '%sgrep -i %q' "${filter:-}${filter:+ | }" "$search_term"
         else
             ## First character is a dash: hide lines that match this
             ## $search_term
             #
             ## Remove the first character (-) before adding to our filter command
-            filter="${filter:-}${filter:+ | }grep -v -i $(shellquote "${search_term:1}")"
+            printf -v filter '%sgrep -v -i %q' "${filter:-}${filter:+ | }" "${search_term:1}"
         fi
     done
 
@@ -1047,7 +1042,7 @@ hasCustomAction()
     return 1
 }
 
-export -f cleaninput getPrefix getTodo getNewtodo shellquote filtercommand _list listWordsWithSigil getPadding _format die
+export -f cleaninput getPrefix getTodo getNewtodo filtercommand _list listWordsWithSigil getPadding _format die
 
 # == HANDLE ACTION ==
 action=$( printf "%s\n" "$ACTION" | tr '[:upper:]' '[:lower:]' )