diff -ur v7/fsyn.py v8/fsyn.py
--- v7/fsyn.py	2020-05-03 01:43:08.000000000 +0900
+++ v8/fsyn.py	2020-05-03 13:13:09.000000000 +0900
@@ -162,7 +162,7 @@
 		msg_done( 'commit', id )
 
 	def curr():
-		msg = 'curr ' + get_curr()
+		msg = get_curr()
 		dbg.out( msg )
 
 	def log():
@@ -231,21 +231,25 @@
 	def clatest():
 		dbg.out( get_clatest() )
 
-	def get_prev(id):
+	def get_prev(id=''):
+		if not id:
+			id = get_curr()
 		link = get_link( id )
 		return link.from_
 
 	def prev():
-		id = get_prev( get_curr() )
+		id = get_prev()
 		if id:
 			dbg.out( id )
 
-	def get_next(id):
+	def get_next(id=''):
+		if not id:
+			id = get_curr()
 		link = get_link( id )
 		return sorted_ids( link.to )
 
 	def next():
-		ids = get_next( get_curr() )
+		ids = get_next()
 		show_ids( ids, 'next' )
 
 	def ckout_org():
@@ -313,7 +317,45 @@
 		ckout_org()
 		ckout( targ_id )
 	
+	def alias_cnv(id):
+		d = {
+			'latest': get_latest,
+			'clatest': get_clatest,
+			'prev': get_prev,
+		}
+		ds = {
+			'next': get_next,
+			'tail': get_tails,
+			'ctail': get_ctails,
+		}
+
+		if id in d:
+			f = d.get( id )
+			return f()
+
+		if id in ds:
+			f = ds.get( id )
+			ids = f()
+			if len( ids ) == 1:
+				return ids[ 0 ]
+			label = id
+			show_ids( ids, label )
+			dbg.err_exit( 'select' )
+
+		for k in ds.keys():
+			if id.startswith( k ):
+				f = ds.get( k )
+				ids = f()
+				i = id[ len( k ) : ]
+				try:
+					i = int( i )
+					return ids[ i ]
+				except:
+					dbg.err_exit( 'id {} ?'.format( id ) )
+		return id
+
 	def checkout(id):
+		id = alias_cnv( id )
 		ckout( id )
 		msg_done( 'checkout', id )
 
@@ -558,7 +600,7 @@
 		arg.cmd_new( 'clatest', comment='show latest id in current chidren' ),
 		arg.cmd_new( 'prev', comment='show prev id' ),
 		arg.cmd_new( 'next', comment='show next ids' ),
-		arg.cmd_new( 'checkout', [ 'id' ] ),
+		arg.cmd_new( 'checkout', [ 'id' ], comment='alias is used instead of id' ),
 		arg.cmd_new( 'check', comment='show dirty' ),
 		arg.cmd_new( 'fixlink', comment='fix link info' ),
 		arg.cmd_new( 'push', [ 'to_path' ] ),