date 当 echo使用
(base) master@origin:~/Documents$ date +ffff
ffff
(base) master@origin:~/Documents$ date +andasfwefqwefdf >> a.txt
(base) master@origin:~/Documents$ cat a.txt
asdf
andasfwefqwefdf
(base) master@origin:~/Documents$ date +ffff
ffff
(base) master@origin:~/Documents$ date +andasfwefqwefdf >> a.txt
(base) master@origin:~/Documents$ cat a.txt
asdf
andasfwefqwefdf