diff --git a/sh/core/code.awk b/sh/core/code.awk
index 0e7042c..2286f33 100644
--- a/sh/core/code.awk
+++ b/sh/core/code.awk
@@ -66,6 +66,21 @@ function doc_reset() {
 	}
 }
 
+# ╭──────┬───────────┬─────╮
+# │ code │ functions │ ids │
+# ╰──────┴───────────┴─────╯
+
+function ids_get(type) {
+	return ids[type]
+}
+
+function ids_put(type, name) {
+	if (ids[type]) {
+		ids[type] = ids[type] "\n"
+	}
+	ids[type] = ids[type] name
+}
+
 # ╭──────┬───────────┬───────╮
 # │ code │ functions │ strip │
 # ╰──────┴───────────┴───────╯
@@ -180,16 +195,19 @@ function parse(string) {
 	} else if (match(string, re["constant"])) {
 		current_match = "constant"
 		constant = strip_value(string)
+		ids_put(current_match, constant)
 
 	# variable
 	} else if (match(string, re["variable"])) {
 		current_match = "variable"
 		variable = strip_value(string)
+		ids_put(current_match, variable)
 
 	# alias
 	} else if (match(string, re["alias"])) {
 		current_match = "alias"
 		alias = strip_first(string, "#=")
+		ids_put(current_match, alias)
 		aliases[alias] = ""
 		doc_append("= " alias)
 
@@ -197,6 +215,7 @@ function parse(string) {
 	} else if (match(string, re["command"])) {
 		current_match = "command"
 		command = strip_first(string, "#/")
+		ids_put(current_match, command)
 		commands[command] = ""
 		doc_append("/ " command)
 
@@ -204,6 +223,7 @@ function parse(string) {
 	} else if (match(string, re["function"])) {
 		current_match = "function"
 		current_function = strip_function(string)
+		ids_put(current_match, current_function)
 
 	# task
 	} else if (match(string, RE_TASK)) {
@@ -357,12 +377,6 @@ if (action == "doc") {
 		doc_reset()
 	}
 
-# filter
-} else if (action == "filter") {
-	if (match($0, re[target])) {
-		unique[extract($0, target)] = ""
-	}
-
 # lint
 } else if (action == "lint") {
 	parse($0)
@@ -380,6 +394,10 @@ if (action == "doc") {
 	# TODO unique command
 	# TODO unique function
 
+# filter
+} else if (action == "filter") {
+	parse($0)
+
 # unknown
 } else {
 	print "unknown action: " action
@@ -436,9 +454,7 @@ END {
 
 	# filter
 	if (action == "filter") {
-		for (item in unique) {
-			print item
-		}
+		print ids_get(target)
 
 	# lint
 	} else if (action == "lint") {