Optimization: Put grep -v empty task filter inside sed.

No need to spawn off another process for this; we can do this inside the sed command that joins the task numbers with the task text.

todo.sh

@@ -775,8 +775,12 @@ _list() {
     fi
     items=$(
         sed = "$src"                                            \
-        | sed "N; s/^/     /; s/ *\(.\{$PADDING,\}\)\n/\1 /"    \
-        | grep -v "^[ 0-9]\+ *$"
+        | sed '''
+            N
+            s/^/     /
+            s/ *\([ 0-9]\{'"$PADDING"',\}\)\n/\1 /
+            /^[ 0-9]\+ *$/d
+         '''
     )
     if [ "${filter_command}" ]; then
         filtered_items=$(echo -n "$items" | eval "${filter_command}")

todo_completion

@@ -38,28 +38,20 @@ _todo()
                     +*) completions=$(TODOTXT_VERBOSE=0 todo.sh command listproj);;
                     @*) completions=$(TODOTXT_VERBOSE=0 todo.sh command listcon);;
                     *)  if [[ "$cur" =~ ^[0-9]+$ ]]; then
+                            local item=$(TODOTXT_VERBOSE=0 todo.sh -@ -+ -p -x command ls "^ *${cur} " | head -n 1)
+
                             # Remove the (padded) task number; we prepend the
-                            # user-provided $cur instead.
-                            # Remove the timestamp prepended by the -t option,
-                            # and the done date (for done tasks); there's no
-                            # todo.txt option for that yet.
-                            # But keep priority and "x"; they're short and may
-                            # provide useful context.
-                            # Remove any trailing whitespace; the Bash
-                            # completion inserts a trailing space itself.
-                            # Finally, limit the output to a single line just as
-                            # a safety check of the ls action output.
-                            local todo=$( \
-                                TODOTXT_VERBOSE=0 todo.sh -@ -+ -p -x command ls "^ *${cur} " | \
-                                sed -e 's/^ *[0-9]\+ //' -e 's/\((.) \)[0-9]\{2,4\}-[0-9]\{2\}-[0-9]\{2\} /\1/' \
-                                    -e 's/\([xX] \)\([0-9]\{2,4\}-[0-9]\{2\}-[0-9]\{2\} \)\{1,2\}/\1/' \
-                                    -e 's/[[:space:]]*$//' \
-                                    -e '1q' \
-                            )
+                            # user-provided $cur.
+                            item=${item#* }
+
+                            # Remove the timestamp prepended by the -t option;
+                            # there's no todo.txt option for that yet.
+                            item=${item#[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9] }
+
                             # Append task text as a shell comment. This
                             # completion can be a safety check before a
                             # destructive todo.txt operation.
-                            [ "$todo" ] && COMPREPLY[0]="$cur # $todo"
+                            [ "$item" ] && COMPREPLY[0]="$cur # $item"
                             return 0
                         else
                             return 0