ENH: Add file completion for move.

This enhancement to todo_completion requires a small enhancement to the listfile action: When no SRC is specified, the list of text files in the todo.txt directory is printed. This is probably also useful on its own, and better than the original behavior of printing "TODO: File  does not exist."

Note: I intentionally omitted bullet-proof error handling ($TODO_DIR non-existing or no text files contained), to avoid over-complicating this.

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/t0100-code-nobacktick.sh

@@ -5,11 +5,12 @@ test_description='no old-style backtick command substitution
 This test checks the todo.sh script itself for occurrences
 of old-style backtick command substitution, which should be
 replaced with $(...).
+On failure, it will print each offending line number and line.
 '
 . ./test-lib.sh
 
 test_todo_session 'no old-style backtick command substitution' <<EOF
->>> sed -n -e 's/[ \t]#.*//' -e '/\d96/{=;p}' "$(which todo.sh)"
+>>> sed -n -e 's/\(^\|[ \t]\)#.*//' -e '/\`/{' -e '=;p' -e '}' "$(which todo.sh)"
 EOF
 
 test_done

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

@@ -53,6 +53,25 @@ TODO: 2 prioritized (C).
 --
 TODO: 3 of 3 tasks shown
 
+>>> todo.sh add "smell the coffee +wakeup"
+4 smell the coffee +wakeup
+TODO: 4 added.
+
+>>> todo.sh -p list
+1 (B) smell the uppercase Roses +flowers @outside
+2 (C) notice the sunflowers
+4 smell the coffee +wakeup
+3 stop
+--
+TODO: 4 of 4 tasks shown
+EOF
+
+cat > todo.txt <<EOF
+(B) smell the uppercase Roses +flowers @outside
+(C) notice the sunflowers
+stop
+EOF
+test_todo_session 'reprioritize' <<EOF
 >>> todo.sh pri 2 A
 2 (A) notice the sunflowers
 TODO: 2 re-prioritized from (C) to (A).
@@ -68,23 +87,11 @@ TODO: 3 of 3 tasks shown
 2 (A) notice the sunflowers
 TODO: 2 already prioritized (A).
 
->>> todo.sh -p listpri
-2 (A) notice the sunflowers
-1 (B) smell the uppercase Roses +flowers @outside
---
-TODO: 2 of 3 tasks shown
-
->>> todo.sh add "smell the coffee +wakeup"
-4 smell the coffee +wakeup
-TODO: 4 added.
-
 >>> todo.sh -p list
 2 (A) notice the sunflowers
 1 (B) smell the uppercase Roses +flowers @outside
-4 smell the coffee +wakeup
 3 stop
 --
-TODO: 4 of 4 tasks shown
+TODO: 3 of 3 tasks shown
 EOF
-
 test_done

tests/t1250-listpri.sh

@@ -4,13 +4,6 @@ test_description='list priority functionality
 '
 . ./test-lib.sh
 
-test_todo_session 'listpri usage' <<EOF
->>> todo.sh listpri ?
-usage: todo.sh listpri PRIORITY
-note: PRIORITY must a single letter from A to Z.
-=== 1
-EOF
-
 cat > todo.txt <<EOF
 (B) smell the uppercase Roses +flowers @outside
 (C) notice the sunflowers
@@ -42,7 +35,7 @@ cat > todo.txt <<EOF
 (n) not a prioritized task
 notice the (C)opyright
 EOF
-test_todo_session 'listpri filtering' <<EOF
+test_todo_session 'listpri filtering priorities' <<EOF
 >>> todo.sh -p listpri
 1 (B) smell the uppercase Roses +flowers @outside
 2 (C) notice the sunflowers
@@ -68,4 +61,35 @@ TODO: 0 of 5 tasks shown
 TODO: 0 of 5 tasks shown
 EOF
 
+cat > todo.txt <<EOF
+(B) ccc xxx this line should be third.
+ccc xxx this line should be third.
+(A) aaa zzz this line should be first.
+aaa zzz this line should be first.
+(B) bbb yyy this line should be second.
+bbb yyy this line should be second.
+EOF
+test_todo_session 'listpri filtering of TERM' <<EOF
+>>> todo.sh -p listpri "should be"
+3 (A) aaa zzz this line should be first.
+5 (B) bbb yyy this line should be second.
+1 (B) ccc xxx this line should be third.
+--
+TODO: 3 of 6 tasks shown
+
+>>> todo.sh -p listpri a "should be"
+3 (A) aaa zzz this line should be first.
+--
+TODO: 1 of 6 tasks shown
+
+>>> todo.sh -p listpri b second
+5 (B) bbb yyy this line should be second.
+--
+TODO: 1 of 6 tasks shown
+
+>>> todo.sh -p listpri x "should be"
+--
+TODO: 0 of 6 tasks shown
+EOF
+
 test_done

tests/t1260-listprj.sh

@@ -0,0 +1,42 @@
+#!/bin/sh
+
+test_description='list project functionality
+'
+. ./test-lib.sh
+
+cat > todo.txt <<EOF
+(B) smell the uppercase Roses +roses @outside +shared
+(C) notice the sunflowers +sunflowers @garden +shared +landscape
+stop
+EOF
+test_todo_session 'basic listproj' <<EOF
+>>> todo.sh listproj
++landscape
++roses
++shared
++sunflowers
+EOF
+
+test_todo_session 'listproj with context' <<EOF
+>>> todo.sh listproj @garden
++landscape
++shared
++sunflowers
+EOF
+
+TEST_TODO_CUSTOM=todo-custom.cfg
+cat todo.cfg > "$TEST_TODO_CUSTOM"
+cat >> "$TEST_TODO_CUSTOM" <<'EOF'
+export DEFAULT='</color>'
+export PRI_B='<color type=green>'
+export PRI_C='<color type=blue>'
+export TODOTXT_FINAL_FILTER='grep -i roses'
+EOF
+test_todo_session 'listproj with context special cases' <<EOF
+>>> todo.sh -+ -d "$TEST_TODO_CUSTOM" listproj @garden
++landscape
++shared
++sunflowers
+EOF
+
+test_done

tests/t1300-ls.sh

@@ -94,6 +94,40 @@ TODO: 1 of 3 tasks shown
 TODO: 1 of 3 tasks shown
 EOF
 
+#
+# check the filtering of TERM containing characters that are special to the
+# shell, like variables, quotes, and multiple subsequent spaces.
+#
+cat > todo.txt <<'EOF'
+earn some pennies
+earn some $$
+earn some "money"
+get money from O'Brian
+just get   money!
+EOF
+test_todo_session 'checking filtering of special characters' <<'EOF'
+>>> todo.sh ls '$$'
+2 earn some $$
+--
+TODO: 1 of 5 tasks shown
+
+>>> todo.sh ls '"money"'
+3 earn some "money"
+--
+TODO: 1 of 5 tasks shown
+
+>>> todo.sh ls "O'Brian"
+4 get money from O'Brian
+--
+TODO: 1 of 5 tasks shown
+
+>>> todo.sh ls "get   money"
+5 just get   money!
+--
+TODO: 1 of 5 tasks shown
+EOF
+
+
 #
 # check the x command line option
 #
@@ -142,7 +176,7 @@ cat > todo.txt <<EOF
 (D) @con02 +prj03 -- Some project 03 task, pri D
 (D) @con02 +prj04 -- Some project 04 task, pri D
 @con01 +prj01 -- Some project 01 task, no priority
-@con01 +prj02 -- Some project 02 task, no priority
+@con01 +prj02 -- Some project(S) 02 task, no priority
 @con02 +prj03 -- Some project 03 task, no priorty
 @con02 +prj04 -- Some project 04 task, no priority
 EOF
@@ -165,7 +199,7 @@ test_todo_session 'plain mode option' <<EOF
 15 (D) @con02 +prj03 -- Some project 03 task, pri D
 16 (D) @con02 +prj04 -- Some project 04 task, pri D
 17 @con01 +prj01 -- Some project 01 task, no priority
-18 @con01 +prj02 -- Some project 02 task, no priority
+18 @con01 +prj02 -- Some project(S) 02 task, no priority
 19 @con02 +prj03 -- Some project 03 task, no priorty
 20 @con02 +prj04 -- Some project 04 task, no priority
 --
@@ -189,7 +223,7 @@ TODO: 20 of 20 tasks shown
 15 (D) @con02 +prj03 -- Some project 03 task, pri D
 16 (D) @con02 +prj04 -- Some project 04 task, pri D
 17 @con01 +prj01 -- Some project 01 task, no priority
-18 @con01 +prj02 -- Some project 02 task, no priority
+18 @con01 +prj02 -- Some project(S) 02 task, no priority
 19 @con02 +prj03 -- Some project 03 task, no priorty
 20 @con02 +prj04 -- Some project 04 task, no priority
 --
@@ -217,7 +251,7 @@ cat > todo.txt <<EOF
 (D) @con02 +prj03 -- Some project 03 task, pri D
 (D) @con02 +prj04 -- Some project 04 task, pri D
 @con01 +prj01 -- Some project 01 task, no priority
-@con01 +prj02 -- Some project 02 task, no priority
+@con01 +prj02 -- Some project(S) 02 task, no priority
 @con02 +prj03 -- Some project 03 task, no priorty
 @con02 +prj04 -- Some project 04 task, no priority
 EOF
@@ -240,7 +274,7 @@ test_todo_session 'context, project, and priority suppression' <<EOF
 15 (D) @con02 +prj03 -- Some project 03 task, pri D
 16 (D) @con02 +prj04 -- Some project 04 task, pri D
 17 @con01 +prj01 -- Some project 01 task, no priority
-18 @con01 +prj02 -- Some project 02 task, no priority
+18 @con01 +prj02 -- Some project(S) 02 task, no priority
 19 @con02 +prj03 -- Some project 03 task, no priorty
 20 @con02 +prj04 -- Some project 04 task, no priority
 --
@@ -256,7 +290,7 @@ TODO: 20 of 20 tasks shown
 13 (D) @con01 +prj01 -- Some project 01 task, pri D
 14 (D) @con01 +prj02 -- Some project 02 task, pri D
 17 @con01 +prj01 -- Some project 01 task, no priority
-18 @con01 +prj02 -- Some project 02 task, no priority
+18 @con01 +prj02 -- Some project(S) 02 task, no priority
 --
 TODO: 10 of 20 tasks shown
 
@@ -270,7 +304,7 @@ TODO: 10 of 20 tasks shown
 13 @con01 +prj01 -- Some project 01 task, pri D
 14 @con01 +prj02 -- Some project 02 task, pri D
 17 @con01 +prj01 -- Some project 01 task, no priority
-18 @con01 +prj02 -- Some project 02 task, no priority
+18 @con01 +prj02 -- Some project(S) 02 task, no priority
 --
 TODO: 10 of 20 tasks shown
 
@@ -284,7 +318,7 @@ TODO: 10 of 20 tasks shown
 13 (D) @con01 -- Some project 01 task, pri D
 14 (D) @con01 -- Some project 02 task, pri D
 17 @con01 -- Some project 01 task, no priority
-18 @con01 -- Some project 02 task, no priority
+18 @con01 -- Some project(S) 02 task, no priority
 --
 TODO: 10 of 20 tasks shown
 
@@ -298,7 +332,7 @@ TODO: 10 of 20 tasks shown
 13 (D) +prj01 -- Some project 01 task, pri D
 14 (D) +prj02 -- Some project 02 task, pri D
 17 +prj01 -- Some project 01 task, no priority
-18 +prj02 -- Some project 02 task, no priority
+18 +prj02 -- Some project(S) 02 task, no priority
 --
 TODO: 10 of 20 tasks shown
 
@@ -312,7 +346,7 @@ TODO: 10 of 20 tasks shown
 13 +prj01 -- Some project 01 task, pri D
 14 +prj02 -- Some project 02 task, pri D
 17 +prj01 -- Some project 01 task, no priority
-18 +prj02 -- Some project 02 task, no priority
+18 +prj02 -- Some project(S) 02 task, no priority
 --
 TODO: 10 of 20 tasks shown
 
@@ -326,7 +360,7 @@ TODO: 10 of 20 tasks shown
 13 (D) @con01 +prj01 -- Some project 01 task, pri D
 14 (D) @con01 +prj02 -- Some project 02 task, pri D
 17 @con01 +prj01 -- Some project 01 task, no priority
-18 @con01 +prj02 -- Some project 02 task, no priority
+18 @con01 +prj02 -- Some project(S) 02 task, no priority
 --
 TODO: 10 of 20 tasks shown
 
@@ -340,7 +374,7 @@ TODO: 10 of 20 tasks shown
 13 -- Some project 01 task, pri D
 14 -- Some project 02 task, pri D
 17 -- Some project 01 task, no priority
-18 -- Some project 02 task, no priority
+18 -- Some project(S) 02 task, no priority
 --
 TODO: 10 of 20 tasks shown
 EOF

tests/t1330-ls-highlighting.sh

@@ -166,4 +166,20 @@ test_todo_session 'highlighting with hidden contexts/projects' <<EOF
 TODO: 4 of 4 tasks shown
 EOF
 
+# check that priorities are only matched at the start of the task
+#
+cat > todo.txt <<EOF
+(D) some prioritized task
+not prioritized
+should not be seen as PRIORITIZE(D) task
+EOF
+test_todo_session 'highlighting priority position' <<EOF
+>>> todo.sh ls
+1 (D) some prioritized task
+2 not prioritized
+3 should not be seen as PRIORITIZE(D) task
+--
+TODO: 3 of 3 tasks shown
+EOF
+
 test_done

todo.sh

@@ -44,39 +44,113 @@ shorthelp()
 
 		  Actions:
 		    add|a "THING I NEED TO DO +project @context"
-		    addto DEST "TEXT TO ADD"
 		    addm "THINGS I NEED TO DO
 		          MORE THINGS I NEED TO DO"
+		    addto DEST "TEXT TO ADD"
 		    append|app ITEM# "TEXT TO APPEND"
 		    archive
 		    command [ACTIONS]
 		    del|rm ITEM# [TERM]
-		    dp|depri ITEM#[, ITEM#, ITEM#, ...]
+		    depri|dp ITEM#[, ITEM#, ITEM#, ...]
 		    do ITEM#[, ITEM#, ITEM#, ...]
 		    help
 		    list|ls [TERM...]
 		    listall|lsa [TERM...]
 		    listcon|lsc
-		    listfile|lf SRC [TERM...]
+		    listfile|lf [SRC [TERM...]]
 		    listpri|lsp [PRIORITY] [TERM...]
-		    listproj|lsprj
+		    listproj|lsprj [TERM...]
 		    move|mv ITEM# DEST [SRC]
 		    prepend|prep ITEM# "TEXT TO PREPEND"
 		    pri|p ITEM# PRIORITY
 		    replace ITEM# "UPDATED TODO"
 		    report
+		    shorthelp
+
+	EndHelp
+
+    # Only list the one-line usage from the add-on actions. This assumes that
+    # add-ons use the same usage indentation structure as todo.sh.
+    addonHelp | grep -e '^  Add-on Actions:' -e '^    [[:alpha:]]'
+
+    cat <<-EndHelpFooter
 
 		  See "help" for more details.
-	EndHelp
+	EndHelpFooter
     exit 0
 }
 
 help()
 {
-    cat <<-EndHelp
+    cat <<-EndOptionsHelp
 		  Usage: $oneline_usage
 
-		  Actions:
+		  Options:
+		    -@
+		        Hide context names in list output. Use twice to show context
+		        names (default).
+		    -+
+		        Hide project names in list output. Use twice to show project
+		        names (default).
+		    -c
+		        Color mode
+		    -d CONFIG_FILE
+		        Use a configuration file other than the default ~/.todo/config
+		    -f
+		        Forces actions without confirmation or interactive input
+		    -h
+		        Display a short help message; same as action "shorthelp"
+		    -p
+		        Plain mode turns off colors
+		    -P
+		        Hide priority labels in list output. Use twice to show
+		        priority labels (default).
+		    -a
+		        Don't auto-archive tasks automatically on completion
+		    -A
+		        Auto-archive tasks automatically on completion
+		    -n
+		        Don't preserve line numbers; automatically remove blank lines
+		        on task deletion
+		    -N
+		        Preserve line numbers
+		    -t
+		        Prepend the current date to a task automatically
+		        when it's added.
+		    -T
+		        Do not prepend the current date to a task automatically
+		        when it's added.
+		    -v
+		        Verbose mode turns on confirmation messages
+		    -vv
+		        Extra verbose mode prints some debugging information and
+		        additional help text
+		    -V
+		        Displays version, license and credits
+		    -x
+		        Disables TODOTXT_FINAL_FILTER
+
+
+	EndOptionsHelp
+
+    [ $TODOTXT_VERBOSE -gt 1 ] && cat <<-EndVerboseHelp
+		  Environment variables:
+		    TODOTXT_AUTO_ARCHIVE            is same as option -a (0)/-A (1)
+		    TODOTXT_CFG_FILE=CONFIG_FILE    is same as option -d CONFIG_FILE
+		    TODOTXT_FORCE=1                 is same as option -f
+		    TODOTXT_PRESERVE_LINE_NUMBERS   is same as option -n (0)/-N (1)
+		    TODOTXT_PLAIN                   is same as option -p (1)/-c (0)
+		    TODOTXT_DATE_ON_ADD             is same as option -t (1)/-T (0)
+		    TODOTXT_VERBOSE=1               is same as option -v
+		    TODOTXT_DISABLE_FILTER=1        is same as option -x
+		    TODOTXT_DEFAULT_ACTION=""       run this when called with no arguments
+		    TODOTXT_SORT_COMMAND="sort ..." customize list output
+		    TODOTXT_FINAL_FILTER="sed ..."  customize list after color, P@+ hiding
+
+
+	EndVerboseHelp
+    cat <<-EndActionsHelp
+		  Built-in Actions:
 		    add "THING I NEED TO DO +project @context"
 		    a "THING I NEED TO DO +project @context"
 		      Adds THING I NEED TO DO to your todo.txt file on its own line.
@@ -137,11 +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...]
@@ -177,81 +253,33 @@ help()
 		    report
 		      Adds the number of open tasks and done tasks to report.txt.
 
+		    shorthelp
+		      List the one-line usage of all built-in and add-on actions.
 
 
-		  Options:
-		    -@
-		        Hide context names in list output. Use twice to show context
-		        names (default).
-		    -+
-		        Hide project names in list output. Use twice to show project
-		        names (default).
-		    -c
-		        Color mode
-		    -d CONFIG_FILE
-		        Use a configuration file other than the default ~/.todo/config
-		    -f
-		        Forces actions without confirmation or interactive input
-		    -h
-		        Display a short help message
-		    -p
-		        Plain mode turns off colors
-		    -P
-		        Hide priority labels in list output. Use twice to show
-		        priority labels (default).
-		    -a
-		        Don't auto-archive tasks automatically on completion
-		    -A
-		        Auto-archive tasks automatically on completion
-		    -n
-		        Don't preserve line numbers; automatically remove blank lines
-		        on task deletion
-		    -N
-		        Preserve line numbers
-		    -t
-		        Prepend the current date to a task automatically
-		        when it's added.
-		    -T
-		        Do not prepend the current date to a task automatically
-		        when it's added.
-		    -v
-		        Verbose mode turns on confirmation messages
-		    -vv
-		        Extra verbose mode prints some debugging information
-		    -V
-		        Displays version, license and credits
-		    -x
-		        Disables TODOTXT_FINAL_FILTER
+	EndActionsHelp
 
+        addonHelp
+    exit 1
+}
 
-		  Environment variables:
-		    TODOTXT_AUTO_ARCHIVE            is same as option -a (0)/-A (1)
-		    TODOTXT_CFG_FILE=CONFIG_FILE    is same as option -d CONFIG_FILE
-		    TODOTXT_FORCE=1                 is same as option -f
-		    TODOTXT_PRESERVE_LINE_NUMBERS   is same as option -n (0)/-N (1)
-		    TODOTXT_PLAIN                   is same as option -p (1)/-c (0)
-		    TODOTXT_DATE_ON_ADD             is same as option -t (1)/-T (0)
-		    TODOTXT_VERBOSE=1               is same as option -v
-		    TODOTXT_DEFAULT_ACTION=""       run this when called with no arguments
-		    TODOTXT_SORT_COMMAND="sort ..." customize list output
-		    TODOTXT_FINAL_FILTER="sed ..."  customize list after color, P@+ hiding
-	EndHelp
-
-    if [ -d "$TODO_ACTIONS_DIR" ]
-    then
-        echo ""
+addonHelp()
+{
+    if [ -d "$TODO_ACTIONS_DIR" ]; then
+        didPrintAddonActionsHeader=
         for action in "$TODO_ACTIONS_DIR"/*
         do
-            if [ -f "$action" -a -x "$action" ]
-            then
+            if [ -f "$action" -a -x "$action" ]; then
+                if [ ! "$didPrintAddonActionsHeader" ]; then
+                    cat <<-EndAddonActionsHeader
+		  Add-on Actions:
+	EndAddonActionsHeader
+                    didPrintAddonActionsHeader=1
+                fi
                 "$action" usage
             fi
         done
-        echo ""
     fi
-
-
-    exit 1
 }
 
 die()
@@ -418,7 +446,10 @@ do
         OVR_TODOTXT_FORCE=1
         ;;
     h )
-        shorthelp
+        # Short-circuit option parsing and forward to the action.
+        # Cannot just invoke shorthelp() because we need the configuration
+        # processed to locate the add-on actions directory.
+        set -- '-h' 'shorthelp'
         ;;
     n )
         OVR_TODOTXT_PRESERVE_LINE_NUMBERS=0
@@ -474,6 +505,7 @@ TODOTXT_AUTO_ARCHIVE=${TODOTXT_AUTO_ARCHIVE:-1}
 TODOTXT_DATE_ON_ADD=${TODOTXT_DATE_ON_ADD:-0}
 TODOTXT_DEFAULT_ACTION=${TODOTXT_DEFAULT_ACTION:-}
 TODOTXT_SORT_COMMAND=${TODOTXT_SORT_COMMAND:-env LC_COLLATE=C sort -f -k2}
+TODOTXT_DISABLE_FILTER=${TODOTXT_DISABLE_FILTER:-}
 TODOTXT_FINAL_FILTER=${TODOTXT_FINAL_FILTER:-cat}
 
 # Export all TODOTXT_* variables
@@ -633,6 +665,42 @@ _addto() {
     fi
 }
 
+shellquote()
+{
+    typeset -r qq=\'; printf %s\\n "'${1//\'/${qq}\\${qq}${qq}}'";
+}
+
+filtercommand()
+{
+    filter=${1:-}
+    shift
+    post_filter=${1:-}
+    shift
+
+    for search_term
+    do
+        ## See if the first character of $search_term is a dash
+        if [ "${search_term:0:1}" != '-' ]
+        then
+            ## First character isn't a dash: hide lines that don't match
+            ## this $search_term
+            filter="${filter:-}${filter:+ | }grep -i $(shellquote "$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 "${search_term:1}")'"
+        fi
+    done
+
+    [ -n "$post_filter" ] && {
+        filter="${filter:-}${filter:+ | }${post_filter:-}"
+    }
+
+    printf %s "$filter"
+}
+
 _list() {
     local FILE="$1"
     ## If the file starts with a "/" use absolute path. Otherwise,
@@ -656,32 +724,8 @@ _list() {
     ## Get our search arguments, if any
     shift ## was file name, new $1 is first search term
 
-    ## Prefix the filter_command with the pre_filter_command
-    filter_command="${pre_filter_command:-}"
-
-    for search_term
-    do
-        ## See if the first character of $search_term is a dash
-        if [ "${search_term:0:1}" != '-' ]
-        then
-            ## First character isn't a dash: hide lines that don't match
-            ## this $search_term
-            filter_command="${filter_command:-} ${filter_command:+|} \
-                grep -i \"$search_term\" "
-        else
-            ## First character is a dash: hide lines that match this
-            ## $search_term
-            #
-            ## Remove the first character (-) before adding to our filter command
-            filter_command="${filter_command:-} ${filter_command:+|} \
-                grep -v -i \"${search_term:1}\" "
-        fi
-    done
-
-    ## If post_filter_command is set, append it to the filter_command
-    [ -n "$post_filter_command" ] && {
-        filter_command="${filter_command:-}${filter_command:+ | }${post_filter_command:-}"
-    }
+    ## Build the filter.
+    filter_command=$(filtercommand "${pre_filter_command:-}" "${post_filter_command:-}" "$@")
 
     ## Figure out how much padding we need to use
     ## We need one level of padding for each power of 10 $LINES uses
@@ -699,7 +743,7 @@ _list() {
         | grep -v "^[ 0-9]\+ *$"
     )
     if [ "${filter_command}" ]; then
-        filtered_items=$(echo -n "$items" | eval ${filter_command})
+        filtered_items=$(echo -n "$items" | eval "${filter_command}")
     else
         filtered_items=$items
     fi
@@ -720,17 +764,18 @@ _list() {
                 return color
             }
             {
-                pos = match($0, /\([A-Z]\)/)
                 if (match($0, /^[0-9]+ x /)) {
                     print highlight("COLOR_DONE") $0 highlight("DEFAULT")
-                } else if (pos > 0) {
-                    clr = highlight("PRI_" substr($0, pos+1, 1))
-                    print ( clr ? clr : highlight("PRI_X") ) $0 highlight("DEFAULT")
+                } else if (match($0, /^[0-9]+ \([A-Z]\)[[:space:]]/)) {
+                    clr = highlight("PRI_" substr($0, RSTART + RLENGTH - 3, 1))
+                    print \
+                        (clr ? clr : highlight("PRI_X")) \
+                        (ENVIRON["HIDE_PRIORITY_SUBSTITUTION"] == "" ? $0 : substr($0, 1, RLENGTH - 4) substr($0, RSTART + RLENGTH)) \
+                        highlight("DEFAULT")
                 } else { print }
             }
           '''  \
         | sed '''
-            s/'${HIDE_PRIORITY_SUBSTITUTION:-^}'//g
             s/'${HIDE_PROJECTS_SUBSTITUTION:-^}'//g
             s/'${HIDE_CONTEXTS_SUBSTITUTION:-^}'//g
           '''                                                   \
@@ -752,7 +797,7 @@ _list() {
     fi
 }
 
-export -f cleaninput _list die
+export -f cleaninput shellquote filtercommand _list die
 
 # == HANDLE ACTION ==
 action=$( printf "%s\n" "$ACTION" | tr 'A-Z' 'a-z' )
@@ -923,7 +968,7 @@ case $action in
 	todo=$(sed "$item!d" "$TODO_FILE")
 	[ -z "$todo" ] && die "TODO: No task $item."
 
-	if sed "$item!d" "$TODO_FILE" | grep "^(.) " > /dev/null; then
+	if [[ "$todo" = \(?\)\ * ]]; then
 	    sed -i.bak -e $item"s/^(.) //" "$TODO_FILE"
 	    if [ $TODOTXT_VERBOSE -gt 0 ]; then
 		NEWTODO=$(sed "$item!d" "$TODO_FILE")
@@ -982,6 +1027,16 @@ case $action in
     help # just in case something failed above, we go ahead and just spew to STDOUT
     ;;
 
+"shorthelp" )
+    if [ -t 1 ] ; then # STDOUT is a TTY
+        if which "${PAGER:-less}" >/dev/null 2>&1; then
+            # we have a working PAGER (or less as a default)
+            shorthelp | "${PAGER:-less}" && exit 0
+        fi
+    fi
+    shorthelp # just in case something failed above, we go ahead and just spew to STDOUT
+    ;;
+
 "list" | "ls" )
     shift  ## Was ls; new $1 is first search term
     _list "$TODO_FILE" "$@"
@@ -996,10 +1051,15 @@ case $action in
 
 "listfile" | "lf" )
     shift  ## Was listfile, next $1 is file name
+    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 "$FILE" "$@"
+    fi
     ;;
 
 "listcon" | "lsc" )
@@ -1007,24 +1067,14 @@ case $action in
     ;;
 
 "listproj" | "lsprj" )
-    grep -o '[^ ]*+[^ ]\+' "$TODO_FILE" | grep '^+' | sort -u
+    shift
+    eval "$(filtercommand 'cat "$TODO_FILE"' '' "$@")" | grep -o '[^ ]*+[^ ]\+' | grep '^+' | sort -u
     ;;
 
 "listpri" | "lsp" )
     shift ## was "listpri", new $1 is priority to list or first TERM
 
-    if [ "${1:-}" ]
-    then
-        ## A priority was specified
-        pri=$( printf "%s\n" "$1" | tr 'a-z' 'A-Z' | grep '^[A-Z]$' ) || {
-            die "usage: $TODO_SH listpri PRIORITY
-note: PRIORITY must a single letter from A to Z."
-        }
-    else
-        ## No priority specified; show all priority tasks
-        pri="[A-Z]"
-    fi
-
+    pri=$(printf "%s\n" "$1" | tr 'a-z' 'A-Z' | grep '^[A-Z]$') && shift || pri="[A-Z]"
     post_filter_command="grep '^ *[0-9]\+ (${pri}) '"
     _list "$TODO_FILE" "$@"
     ;;

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