ls -l --time-style=full-iso
ls --full-time

从手册页：

–time-style=STYLE
with -l,show times using style STYLE: full-iso,long-iso,iso,locale,+FORMAT. FORMAT is interpreted like date'; if
FORMAT is FORMAT1<newline>FORMAT2,FORMAT1 applies to non-recent files
and FORMAT2 to recent files; if STYLE is prefixed withposix-‘,
STYLE takes effect only outside the POSIX locale

所以你也可以有一个格式说明符(见格式字符串的日期手册页)：

ls -l --time-style=+"%Y %H:%M:%S"