ls命令中的 time-style

在使用ls命令时，ls -l  默认只显示“月-日”，而不显示“年”，这样就给我们查看文件的时间属性带来困扰，这时侯，我们可以指定time-style（时间显示类型）。
       linux中time-style的参数为：
 - `full-iso'
  - `long-iso'
  - `iso'
  - `locale'
具体解释如下。（）--time-style=style’List timestamps in style.style. Thestyleshould be one of the following:‘+format’List timestamps usingformat, whereformatis interpreted like the format argument ofdate(see). For example,--time-style="+%Y-%m-%d %H:%M:%S"causeslsto list timestamps like ‘2002-03-30 23:45:56’. As withdate,format's interpretation is affected by theLC_TIMElocale category.

Ifformatcontains two format strings separated by a newline, the former is used for non-recent files and the latter for recent files; if you want output columns to line up, you may need to insert spaces in one of the two formats.

‘full-iso’List timestamps in full usingISO8601 date, time, and time zone format with nanosecond precision, e.g., ‘2002-03-30 23:45:56.477817180 -0700’. This style. is equivalent to ‘+%Y-%m-%d %H:%M:%S.%N %z’.

This is useful because the time output includes all the information that is available from the operating system. For example, this can help explainmake's behavior, sinceGNUmakeuses the full timestamp to determine whether a file is out of date.

‘long-iso’ListISO8601 date and time in minutes, e.g., ‘2002-03-30 23:45’. These timestamps are shorter than ‘full-iso’ timestamps, and are usually good enough for everyday work. This style. is equivalent to ‘+%Y-%m-%d %H:%M’.
‘iso’ListISO8601 dates for non-recent timestamps (e.g., ‘2002-03-30’), andISO8601 month, day, hour, and minute for recent timestamps (e.g., ‘03-30 23:45’). These timestamps are uglier than ‘long-iso’ timestamps, but they carry nearly the same information in a smaller space and their brevity helpslsoutput fit within traditional 80-column output lines. The following twolsinvocations are equivalent:newline='
'
ls -l --time-style="+%Y-%m-%d $newline%m-%d %H:%M"
ls -l --time-style="iso"

‘locale’List timestamps in a locale-dependent form. For example, a Finnish locale might list non-recent timestamps like ‘maalis 30 2002’ and recent timestamps like ‘maalis 30 23:45’. Locale-dependent timestamps typically consume more space than ‘iso’ timestamps and are harder for programs to parse because locale conventions vary so widely, but they are easier for many people to read.

TheLC_TIMElocale category specifies the timestamp format. The defaultPOSIXlocale uses timestamps like ‘Mar 30 2002’ and ‘Mar 30 23:45’; in this locale, the following twolsinvocations are equivalent:

newline='
'
ls -l --time-style="+%b %e %Y$newline%b %e %H:%M"
ls -l --time-style="locale"

Other locales behave differently. For example, in a German locale,--time-style="locale"might be equivalent to--time-style="+%e. %b %Y $newline%e. %b %H:%M"and might generate timestamps like ‘30. Mär 2002’ and ‘30. Mär 23:45’.

‘posix-style’ListPOSIX-locale timestamps if theLC_TIMElocale category isPOSIX,styletimestamps otherwise. For example, the ‘posix-long-iso’ style. lists timestamps like ‘Mar 30 2002’ and ‘Mar 30 23:45’ when in thePOSIXlocale, and like ‘2002-03-30 23:45’ otherwise.

You can specify the default value of the--time-styleoption with the environment variableTIME_STYLE; ifTIME_STYLEis not set the default style. is ‘locale’.GNUEmacs 21.3 and later use the--diredoption and therefore can parse any date format, but if you are using Emacs 21.1 or 21.2 and specify a non-POSIXlocale you may need to set ‘TIME_STYLE="posix-long-iso"’.