ENH: listall doesn't simply use concatenated task lists.

The simplistic "listall" action implementation just uses _list() on the concatenation of active and done task lists. This has the following shortcomings:

- Task numbers shown for archived tasks from done.txt are invalid.
- As the number of done tasks likely greatly outnumbers the number of active tasks, the task number padding is often larger than expected (e.g. 0005 instead of 05).
- Verbose output lists all tasks as originating from TODO, whereas it should differentiate between TODO: and DONE: sources.

The main challenge is to keep processing all tasks through a single pass of _list(), so that there is a single, unified sorting applied to all tasks. A custom AWK script sets all (originally invalid) task numbers from done.txt to "0", meaning "archived task".
The verbose message from _list() is replaced with a custom message that shows the tasks from todo.txt, done.txt, and totals.

Oh, and added tests for the previously untested "listall" action.

Makefile

@@ -13,7 +13,7 @@ VERSION-FILE: .FORCE-VERSION-FILE
 todo.sh: VERSION-FILE
 
 # For packaging
-DISTFILES := todo.cfg
+DISTFILES := todo.cfg todo_completion
 
 DISTNAME=todo.txt_cli-$(VERSION)
 dist: $(DISTFILES) todo.sh

tests/t0001-null.sh

@@ -45,6 +45,8 @@ test_expect_success 'null listpri a' '
 cat > expect <<EOF
 --
 TODO: 0 of 0 tasks shown
+DONE: 0 of 0 tasks shown
+total 0 of 0 tasks shown
 EOF
 
 test_expect_success 'null lsa' '

tests/t1020-addtolistfile.sh

@@ -39,6 +39,24 @@ GARDEN: 2 added.
 GARDEN: 2 of 2 tasks shown
 EOF
 
+#
+# List available files
+#
+test_todo_session 'list available files' <<EOF
+>>> todo.sh listfile
+Files in the todo.txt directory:
+done.txt
+garden.txt
+report.txt
+todo.txt
+
+>>> TODOTXT_VERBOSE=0 todo.sh listfile
+done.txt
+garden.txt
+report.txt
+todo.txt
+EOF
+
 #
 # Filter
 #

tests/t1200-pri.sh

@@ -66,6 +66,12 @@ TODO: 4 added.
 TODO: 4 of 4 tasks shown
 EOF
 
+test_todo_session 'priority error' <<EOF
+>>> todo.sh pri 10 B
+=== 1
+TODO: No task 10.
+EOF
+
 cat > todo.txt <<EOF
 (B) smell the uppercase Roses +flowers @outside
 (C) notice the sunflowers

tests/t1350-listall.sh

@@ -0,0 +1,150 @@
+#!/bin/sh
+
+test_description='listall functionality
+'
+. ./test-lib.sh
+
+cat > todo.txt <<EOF
+smell the uppercase Roses +flowers @outside
+x 2011-08-08 tend the garden @outside
+notice the sunflowers
+x 2011-12-26 go outside +wakeup
+(A) stop
+EOF
+cat > done.txt <<EOF
+x 2011-12-01 eat breakfast
+x 2011-12-05 smell the coffee +wakeup
+EOF
+
+test_todo_session 'basic listall' <<EOF
+>>> todo.sh -p listall
+5 (A) stop
+3 notice the sunflowers
+1 smell the uppercase Roses +flowers @outside
+2 x 2011-08-08 tend the garden @outside
+0 x 2011-12-01 eat breakfast
+0 x 2011-12-05 smell the coffee +wakeup
+4 x 2011-12-26 go outside +wakeup
+--
+TODO: 5 of 5 tasks shown
+DONE: 2 of 2 tasks shown
+total 7 of 7 tasks shown
+EOF
+
+test_todo_session 'listall highlighting' <<EOF
+>>> todo.sh listall
+5 (A) stop
+3 notice the sunflowers
+1 smell the uppercase Roses +flowers @outside
+2 x 2011-08-08 tend the garden @outside
+0 x 2011-12-01 eat breakfast
+0 x 2011-12-05 smell the coffee +wakeup
+4 x 2011-12-26 go outside +wakeup
+--
+TODO: 5 of 5 tasks shown
+DONE: 2 of 2 tasks shown
+total 7 of 7 tasks shown
+EOF
+
+test_todo_session 'listall nonverbose' <<EOF
+>>> TODOTXT_VERBOSE=0 todo.sh -p listall
+5 (A) stop
+3 notice the sunflowers
+1 smell the uppercase Roses +flowers @outside
+2 x 2011-08-08 tend the garden @outside
+0 x 2011-12-01 eat breakfast
+0 x 2011-12-05 smell the coffee +wakeup
+4 x 2011-12-26 go outside +wakeup
+EOF
+
+test_todo_session 'listall filtering' <<EOF
+>>> todo.sh -p listall @outside
+1 smell the uppercase Roses +flowers @outside
+2 x 2011-08-08 tend the garden @outside
+--
+TODO: 2 of 5 tasks shown
+DONE: 0 of 2 tasks shown
+total 2 of 7 tasks shown
+
+>>> todo.sh -p listall the
+3 notice the sunflowers
+1 smell the uppercase Roses +flowers @outside
+2 x 2011-08-08 tend the garden @outside
+0 x 2011-12-05 smell the coffee +wakeup
+--
+TODO: 3 of 5 tasks shown
+DONE: 1 of 2 tasks shown
+total 4 of 7 tasks shown
+
+>>> todo.sh -p listall breakfast
+0 x 2011-12-01 eat breakfast
+--
+TODO: 0 of 5 tasks shown
+DONE: 1 of 2 tasks shown
+total 1 of 7 tasks shown
+
+>>> todo.sh -p listall doesnotmatch
+--
+TODO: 0 of 5 tasks shown
+DONE: 0 of 2 tasks shown
+total 0 of 7 tasks shown
+EOF
+
+cat >> done.txt <<EOF
+x 2010-01-01 old task 1
+x 2010-01-01 old task 2
+x 2010-01-01 old task 3
+x 2010-01-01 old task 4
+EOF
+test_todo_session 'listall number width' <<EOF
+>>> todo.sh -p listall
+5 (A) stop
+3 notice the sunflowers
+1 smell the uppercase Roses +flowers @outside
+0 x 2010-01-01 old task 1
+0 x 2010-01-01 old task 2
+0 x 2010-01-01 old task 3
+0 x 2010-01-01 old task 4
+2 x 2011-08-08 tend the garden @outside
+0 x 2011-12-01 eat breakfast
+0 x 2011-12-05 smell the coffee +wakeup
+4 x 2011-12-26 go outside +wakeup
+--
+TODO: 5 of 5 tasks shown
+DONE: 6 of 6 tasks shown
+total 11 of 11 tasks shown
+
+>>> TODOTXT_VERBOSE=0 todo.sh add new task 1
+
+>>> TODOTXT_VERBOSE=0 todo.sh add new task 2
+
+>>> TODOTXT_VERBOSE=0 todo.sh add new task 3
+
+>>> TODOTXT_VERBOSE=0 todo.sh add new task 4
+
+>>> TODOTXT_VERBOSE=0 todo.sh add new task 5
+
+>>> todo.sh -p listall
+05 (A) stop
+06 new task 1
+07 new task 2
+08 new task 3
+09 new task 4
+10 new task 5
+03 notice the sunflowers
+01 smell the uppercase Roses +flowers @outside
+00 x 2010-01-01 old task 1
+00 x 2010-01-01 old task 2
+00 x 2010-01-01 old task 3
+00 x 2010-01-01 old task 4
+02 x 2011-08-08 tend the garden @outside
+00 x 2011-12-01 eat breakfast
+00 x 2011-12-05 smell the coffee +wakeup
+04 x 2011-12-26 go outside +wakeup
+--
+TODO: 10 of 10 tasks shown
+DONE: 6 of 6 tasks shown
+total 16 of 16 tasks shown
+EOF
+
+test_done

todo.sh

@@ -57,7 +57,7 @@ shorthelp()
 		    list|ls [TERM...]
 		    listall|lsa [TERM...]
 		    listcon|lsc
-		    listfile|lf SRC [TERM...]
+		    listfile|lf [SRC [TERM...]]
 		    listpri|lsp [PRIORITY] [TERM...]
 		    listproj|lsprj [TERM...]
 		    move|mv ITEM# DEST [SRC]
@@ -211,11 +211,13 @@ help()
 		    lsc
 		      Lists all the task contexts that start with the @ sign in todo.txt.
 
-		    listfile SRC [TERM...]
-		    lf SRC [TERM...]
+		    listfile [SRC [TERM...]]
+		    lf [SRC [TERM...]]
 		      Displays all the lines in SRC file located in the todo.txt directory,
 		      sorted by priority with line  numbers.  If TERM specified, lists
 		      all lines that contain TERM in SRC file.
+		      Without any arguments, the names of all text files in the todo.txt
+		      directory are listed.
 
 		    listpri [PRIORITY] [TERM...]
 		    lsp [PRIORITY] [TERM...]
@@ -294,6 +296,11 @@ cleanup()
 
 cleaninput()
 {
+    # Parameters:    When $1 = "for sed", performs additional escaping for use
+    #                in sed substitution with "|" separators.
+    # Precondition:  $input contains text to be cleaned.
+    # Postcondition: Modifies $input.
+
     # Replace CR and LF with space; tasks always comprise a single line.
     input=${input//$'\r'/ }
     input=${input//$'\n'/ }
@@ -308,6 +315,44 @@ cleaninput()
     fi
 }
 
+getPrefix()
+{
+    # Parameters:    $1: todo file; empty means $TODO_FILE.
+    # Returns:       Uppercase FILE prefix to be used in place of "TODO:" where
+    #                a different todo file can be specified.
+    local base=$(basename "${1:-$TODO_FILE}")
+    echo "${base%%.[^.]*}" | tr 'a-z' 'A-Z'
+}
+
+getTodo()
+{
+    # Parameters:    $1: task number
+    #                $2: Optional todo file
+    # Precondition:  $errmsg contains usage message.
+    # Postcondition: $todo contains task text.
+
+    local item=$1
+    [ -z "$item" ] && die "$errmsg"
+    [ "${item//[0-9]/}" ] && die "$errmsg"
+
+    todo=$(sed "$item!d" "${2:-$TODO_FILE}")
+    [ -z "$todo" ] && die "$(getPrefix "$2"): No task $item."
+}
+getNewtodo()
+{
+    # Parameters:    $1: task number
+    #                $2: Optional todo file
+    # Precondition:  None.
+    # Postcondition: $newtodo contains task text.
+
+    local item=$1
+    [ -z "$item" ] && die 'Programming error: $item should exist.'
+    [ "${item//[0-9]/}" ] && die 'Programming error: $item should be numeric.'
+
+    newtodo=$(sed "$item!d" "${2:-$TODO_FILE}")
+    [ -z "$newtodo" ] && die "$(getPrefix "$2"): No updated task $item."
+}
+
 archive()
 {
     #defragment blank lines
@@ -336,12 +381,7 @@ replaceOrPrepend()
       ;;
   esac
   shift; item=$1; shift
-
-  [ -z "$item" ] && die "$errmsg"
-  [[ "$item" = +([0-9]) ]] || die "$errmsg"
-
-  todo=$(sed "$item!d" "$TODO_FILE")
-  [ -z "$todo" ] && die "TODO: No task $item."
+  getTodo "$item"
 
   if [[ -z "$1" && $TODOTXT_FORCE = 0 ]]; then
     echo -n "$querytext"
@@ -366,7 +406,7 @@ replaceOrPrepend()
   # date again.
   sed -i.bak -e "$item s/^${priority}${prepdate}//" -e "$item s|^.*|${priority}${prepdate}${input}${backref}|" "$TODO_FILE"
   if [ $TODOTXT_VERBOSE -gt 0 ]; then
-    newtodo=$(sed "$item!d" "$TODO_FILE")
+    getNewtodo "$item"
     case "$action" in
       replace)
         echo "$item $todo"
@@ -656,10 +696,8 @@ _addto() {
     echo "$input" >> "$file"
     if [ $TODOTXT_VERBOSE -gt 0 ]; then
         TASKNUM=$(sed -n '$ =' "$file")
-        BASE=$(basename "$file")
-        PREFIX=$(echo ${BASE%%.[^.]*} | tr 'a-z' 'A-Z')
         echo "$TASKNUM $input"
-        echo "${PREFIX}: $TASKNUM added."
+        echo "$(getPrefix "$file"): $TASKNUM added."
     fi
 }
 
@@ -782,20 +820,18 @@ _list() {
     [ "$filtered_items" ] && echo "$filtered_items"
 
     if [ $TODOTXT_VERBOSE -gt 0 ]; then
-        BASE=$(basename "$FILE")
-        PREFIX=$(echo ${BASE%%.[^.]*} | tr 'a-z' 'A-Z')
         NUMTASKS=$( echo -n "$filtered_items" | sed -n '$ =' )
         TOTALTASKS=$( echo -n "$items" | sed -n '$ =' )
 
         echo "--"
-        echo "${PREFIX}: ${NUMTASKS:-0} of ${TOTALTASKS:-0} tasks shown"
+        echo "$(getPrefix "$FILE"): ${NUMTASKS:-0} of ${TOTALTASKS:-0} tasks shown"
     fi
     if [ $TODOTXT_VERBOSE -gt 1 ]; then
         echo "TODO DEBUG: Filter Command was: ${filter_command:-cat}"
     fi
 }
 
-export -f cleaninput shellquote filtercommand _list die
+export -f cleaninput getPrefix getTodo getNewtodo shellquote filtercommand _list die
 
 # == HANDLE ACTION ==
 action=$( printf "%s\n" "$ACTION" | tr 'A-Z' 'a-z' )
@@ -872,11 +908,8 @@ case $action in
 "append" | "app" )
     errmsg="usage: $TODO_SH append ITEM# \"TEXT TO APPEND\""
     shift; item=$1; shift
+    getTodo "$item"
 
-    [ -z "$item" ] && die "$errmsg"
-    [[ "$item" = +([0-9]) ]] || die "$errmsg"
-    todo=$(sed "$item!d" "$TODO_FILE")
-    [ -z "$todo" ] && die "TODO: No task $item."
     if [[ -z "$1" && $TODOTXT_FORCE = 0 ]]; then
         echo -n "Append: "
         read input
@@ -891,7 +924,7 @@ case $action in
 
     if sed -i.bak $item" s|^.*|&${appendspace}${input}|" "$TODO_FILE"; then
         if [ $TODOTXT_VERBOSE -gt 0 ]; then
-            newtodo=$(sed "$item!d" "$TODO_FILE")
+            getNewtodo "$item"
             echo "$item $newtodo"
 	fi
     else
@@ -906,14 +939,11 @@ case $action in
     # replace deleted line with a blank line when TODOTXT_PRESERVE_LINE_NUMBERS is 1
     errmsg="usage: $TODO_SH del ITEM# [TERM]"
     item=$2
-    [ -z "$item" ] && die "$errmsg"
-    [[ "$item" = +([0-9]) ]] || die "$errmsg"
-    DELETEME=$(sed "$item!d" "$TODO_FILE")
-    [ -z "$DELETEME" ] && die "TODO: No task $item."
+    getTodo "$item"
 
     if [ -z "$3" ]; then
         if  [ $TODOTXT_FORCE = 0 ]; then
-            echo "Delete '$DELETEME'?  (y/n)"
+            echo "Delete '$todo'?  (y/n)"
             read ANSWER
         else
             ANSWER="y"
@@ -927,7 +957,7 @@ case $action in
                 sed -i.bak -e $item"s/^.*//" "$TODO_FILE"
             fi
             if [ $TODOTXT_VERBOSE -gt 0 ]; then
-                echo "$item $DELETEME"
+                echo "$item $todo"
                 echo "TODO: $item deleted."
             fi
         else
@@ -941,13 +971,13 @@ case $action in
             -e $item"s/ *$3  */ /g" \
             -e $item"s/$3//g" \
             "$TODO_FILE"
-        newtodo=$(sed "$item!d" "$TODO_FILE")
-        if [ "$DELETEME" = "$newtodo" ]; then
-            [ $TODOTXT_VERBOSE -gt 0 ] && echo "$item $DELETEME"
+        getNewtodo "$item"
+        if [ "$todo" = "$newtodo" ]; then
+            [ $TODOTXT_VERBOSE -gt 0 ] && echo "$item $todo"
             die "TODO: '$3' not found; no removal done."
         fi
         if [ $TODOTXT_VERBOSE -gt 0 ]; then
-            echo "$item $DELETEME"
+            echo "$item $todo"
             echo "TODO: Removed '$3' from task."
             echo "$item $newtodo"
         fi
@@ -962,15 +992,13 @@ case $action in
     # Split multiple depri's, if comma separated change to whitespace separated
     # Loop the 'depri' function for each item
     for item in $(echo $* | tr ',' ' '); do
-	[[ "$item" = +([0-9]) ]] || die "$errmsg"
-	todo=$(sed "$item!d" "$TODO_FILE")
-	[ -z "$todo" ] && die "TODO: No task $item."
+        getTodo "$item"
 
 	if [[ "$todo" = \(?\)\ * ]]; then
 	    sed -i.bak -e $item"s/^(.) //" "$TODO_FILE"
 	    if [ $TODOTXT_VERBOSE -gt 0 ]; then
-		NEWTODO=$(sed "$item!d" "$TODO_FILE")
-		echo "$item $NEWTODO"
+		getNewtodo "$item"
+		echo "$item $newtodo"
 		echo "TODO: $item deprioritized."
 	    fi
 	else
@@ -988,11 +1016,7 @@ case $action in
     # Split multiple do's, if comma separated change to whitespace separated
     # Loop the 'do' function for each item
     for item in $(echo $* | tr ',' ' '); do
-        [ -z "$item" ] && die "$errmsg"
-        [[ "$item" = +([0-9]) ]] || die "$errmsg"
-
-        todo=$(sed "$item!d" "$TODO_FILE")
-        [ -z "$todo" ] && die "TODO: No task $item."
+        getTodo "$item"
 
         # Check if this item has already been done
         if [ "${todo:0:2}" != "x " ]; then
@@ -1001,7 +1025,7 @@ case $action in
             sed -i.bak $item"s/^(.) //" "$TODO_FILE"
             sed -i.bak $item"s|^|x $now |" "$TODO_FILE"
             if [ $TODOTXT_VERBOSE -gt 0 ]; then
-                newtodo=$(sed "$item!d" "$TODO_FILE")
+                getNewtodo "$item"
                 echo "$item $newtodo"
                 echo "TODO: $item marked as done."
 	    fi
@@ -1044,15 +1068,33 @@ case $action in
     shift  ## Was lsa; new $1 is first search term
 
     cat "$TODO_FILE" "$DONE_FILE" > "$TMP_FILE"
-    _list "$TMP_FILE" "$@"
+    TOTAL=$( sed -n '$ =' "$TODO_FILE" )
+
+    post_filter_command="awk -v TOTAL=$TOTAL -v PADDING=${#TOTAL} '{ \$1 = sprintf(\"%\" PADDING \"d\", (\$1 > TOTAL ? 0 : \$1)); print }' "
+    TODOTXT_VERBOSE=0 _list "$TMP_FILE" "$@"
+
+    if [ $TODOTXT_VERBOSE -gt 0 ]; then
+        TDONE=$( sed -n '$ =' "$DONE_FILE" )
+        TASKNUM=$(TODOTXT_PLAIN=1 TODOTXT_VERBOSE=0 _list "$TODO_FILE" "$@" | sed -n '$ =')
+        DONENUM=$(TODOTXT_PLAIN=1 TODOTXT_VERBOSE=0 _list "$DONE_FILE" "$@" | sed -n '$ =')
+        echo "--"
+        echo "$(getPrefix "$TODO_FILE"): ${TASKNUM:-0} of ${TOTAL:-0} tasks shown"
+        echo "$(getPrefix "$DONE_FILE"): ${DONENUM:-0} of ${TDONE:-0} tasks shown"
+        echo "total $((TASKNUM + DONENUM)) of $((TOTAL + TDONE)) tasks shown"
+    fi
     ;;
 
 "listfile" | "lf" )
     shift  ## Was listfile, next $1 is file name
-    FILE="$1"
-    shift  ## Was filename; next $1 is first search term
+    if [ $# -eq 0 ]; then
+        [ $TODOTXT_VERBOSE -gt 0 ] && echo "Files in the todo.txt directory:"
+        cd "$TODO_DIR" && ls -1 *.txt
+    else
+        FILE="$1"
+        shift  ## Was filename; next $1 is first search term
 
-    _list "$FILE" "$@"
+        _list "$FILE" "$@"
+    fi
     ;;
 
 "listcon" | "lsc" )
@@ -1079,19 +1121,16 @@ case $action in
     dest="$TODO_DIR/$3"
     src="$TODO_DIR/$4"
 
-    [ -z "$item" ] && die "$errmsg"
     [ -z "$4" ] && src="$TODO_FILE"
     [ -z "$dest" ] && die "$errmsg"
 
-    [[ "$item" = +([0-9]) ]] || die "$errmsg"
-
     [ -f "$src" ] || die "TODO: Source file $src does not exist."
     [ -f "$dest" ] || die "TODO: Destination file $dest does not exist."
 
-    MOVEME=$(sed "$item!d" "$src")
-    [ -z "$MOVEME" ] && die "$item: No such item in $src."
+    getTodo "$item" "$src"
+    [ -z "$todo" ] && die "$item: No such item in $src."
     if  [ $TODOTXT_FORCE = 0 ]; then
-        echo "Move '$MOVEME' from $src to $dest? (y/n)"
+        echo "Move '$todo' from $src to $dest? (y/n)"
         read ANSWER
     else
         ANSWER="y"
@@ -1104,10 +1143,10 @@ case $action in
             # leave blank line behind (preserves line numbers)
             sed -i.bak -e $item"s/^.*//" "$src"
         fi
-        echo "$MOVEME" >> "$dest"
+        echo "$todo" >> "$dest"
 
         if [ $TODOTXT_VERBOSE -gt 0 ]; then
-            echo "$item $MOVEME"
+            echo "$item $todo"
             echo "TODO: $item moved from '$src' to '$dest'."
         fi
     else
@@ -1128,16 +1167,20 @@ case $action in
 note: PRIORITY must be anywhere from A to Z."
 
     [ "$#" -ne 3 ] && die "$errmsg"
-    [[ "$item" = +([0-9]) ]] || die "$errmsg"
     [[ "$newpri" = @([A-Z]) ]] || die "$errmsg"
+    getTodo "$item"
+
+    oldpri=
+    if [[ "$todo" = \(?\)\ * ]]; then
+        oldpri=${todo:1:1}
+    fi
 
-    oldpri=$(sed -ne $item's/^(\(.\)) .*/\1/p' "$TODO_FILE")
     if [ "$oldpri" != "$newpri" ]; then
         sed -i.bak -e $item"s/^(.) //" -e $item"s/^/($newpri) /" "$TODO_FILE"
     fi
     if [ $TODOTXT_VERBOSE -gt 0 ]; then
-        NEWTODO=$(sed "$item!d" "$TODO_FILE")
-        echo "$item $NEWTODO"
+        getNewtodo "$item"
+        echo "$item $newtodo"
         if [ "$oldpri" != "$newpri" ]; then
             if [ "$oldpri" ]; then
                 echo "TODO: $item re-prioritized from ($oldpri) to ($newpri)."

todo_completion

@@ -0,0 +1,71 @@
+#!/bin/bash source-this-script
+[ "$BASH_VERSION" ] || return
+
+_todo()
+{
+    local cur prev opts
+    COMPREPLY=()
+    cur="${COMP_WORDS[COMP_CWORD]}"
+    prev="${COMP_WORDS[COMP_CWORD-1]}"
+
+    local -r OPTS="-@ -@@ -+ -++ -d -f -h -p -P -PP -a -n -t -v -vv -V -x"
+    local -r COMMANDS="\
+        add a addto addm append app archive command del  \
+        rm depri dp do help list ls listall lsa listcon  \
+        lsc listfile lf listpri lsp listproj lsprj move \
+        mv prepend prep pri p replace report shorthelp"
+
+    # Add custom commands from add-ons, if installed.
+    # TODO: Filter for executable flag of files found in $TODO_ACTIONS_DIR.
+    local allCommands="$COMMANDS $('ls' "${TODO_ACTIONS_DIR:-$HOME/.todo.actions.d}/" 2>/dev/null)"
+
+    local completions
+    if [ $COMP_CWORD -eq 1 ]; then
+        completions="$allCommands $OPTS"
+    elif [[ $COMP_CWORD -gt 2 && ( \
+        "${COMP_WORDS[COMP_CWORD-2]}" =~ ^(move|mv)$ || \
+        "${COMP_WORDS[COMP_CWORD-3]}" =~ ^(move|mv)$ ) ]]; then
+        # "move ITEM# DEST [SRC]" has file arguments on positions 2 and 3.
+        completions=$(TODOTXT_VERBOSE=0 todo.sh command listfile)
+    else
+        case "$prev" in
+            command)
+                completions=$COMMANDS;;
+            addto|listfile|lf)
+                completions=$(TODOTXT_VERBOSE=0 todo.sh command listfile);;
+            -*) completions="$allCommands $OPTS";;
+            *)  case "$cur" in
+                    +*) 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 $cur.
+                            item=${item#* }
+
+                            # Remove the timestamp prepended by the -t option;
+                            # there's no todo.txt option for that yet.
+                            item=${item#[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9] }
+
+                            # Append task text as a shell comment. This
+                            # completion can be a safety check before a
+                            # destructive todo.txt operation.
+                            [ "$item" ] && COMPREPLY[0]="$cur # $item"
+                            return 0
+                        else
+                            return 0
+                        fi
+                        ;;
+                esac
+                ;;
+        esac
+    fi
+
+    COMPREPLY=( $( compgen -W "$completions" -- $cur ))
+    return 0
+}
+complete -F _todo todo.sh
+# If you define an alias (e.g. "t") to todo.sh, you need to explicitly enable
+# completion for it, too:
+#complete -F _todo t