>>677
$ a="2020-04-21 05:11:01 aaa bbb:ccc ddd eee:fff:ggg:"
$ echo "$a" | sed -r 's/(2.*)(:.*:$)/\1/'
2020-04-21 05:11:01 aaa bbb:ccc ddd eee:fff
横着せず全体を指定しないとダメよ