linux date命令详解

朱雀 2021-09-27 10:48 361阅读 0赞

date命令显示当前日期和时间。 它还可以指定的格式显示或计算特定日期。 超级用户（root）可以使用它来设置系统时钟。

使用格式： date \[OPTION\]... \[+FORMAT\]  
date --help显示详细选项（man date查看完整说明）：

$ date --help
    Usage: date [OPTION]... [+FORMAT]
      or:  date [-u|--utc|--universal] [MMDDhhmm[[CC]YY][.ss]]
    Display the current time in the given FORMAT, or set the system date.
    
      -d, --date=STRING         display time described by STRING, not `now'
      -f, --file=DATEFILE       like --date once for each line of DATEFILE
      -r, --reference=FILE      display the last modification time of FILE
      -R, --rfc-2822            output date and time in RFC 2822 format.
                                Example: Mon, 07 Aug 2006 12:34:56 -0600
          --rfc-3339=TIMESPEC   output date and time in RFC 3339 format.
                                TIMESPEC=`date', `seconds', or `ns' for
                                date and time to the indicated precision.
                                Date and time components are separated by
                                a single space: 2006-08-07 12:34:56-06:00
      -s, --set=STRING          set time described by STRING
      -u, --utc, --universal    print or set Coordinated Universal Time
          --help     display this help and exit
          --version  output version information and exit
    
    FORMAT controls the output.  Interpreted sequences are:
    
      %%   a literal %
      %a   locale's abbreviated weekday name (e.g., Sun)
      %A   locale's full weekday name (e.g., Sunday)
      %b   locale's abbreviated month name (e.g., Jan)
      %B   locale's full month name (e.g., January)
      %c   locale's date and time (e.g., Thu Mar  3 23:05:25 2005)
      %C   century; like %Y, except omit last two digits (e.g., 20)
      %d   day of month (e.g, 01)
      %D   date; same as %m/%d/%y
      %e   day of month, space padded; same as %_d
      %F   full date; same as %Y-%m-%d
      %g   last two digits of year of ISO week number (see %G)
      %G   year of ISO week number (see %V); normally useful only with %V
      %h   same as %b
      %H   hour (00..23)
      %I   hour (01..12)
      %j   day of year (001..366)
      %k   hour ( 0..23)
      %l   hour ( 1..12)
      %m   month (01..12)
      %M   minute (00..59)
      %n   a newline
      %N   nanoseconds (000000000..999999999)
      %p   locale's equivalent of either AM or PM; blank if not known
      %P   like %p, but lower case
      %r   locale's 12-hour clock time (e.g., 11:11:04 PM)
      %R   24-hour hour and minute; same as %H:%M
      %s   seconds since 1970-01-01 00:00:00 UTC
      %S   second (00..60)
      %t   a tab
      %T   time; same as %H:%M:%S
      %u   day of week (1..7); 1 is Monday
      %U   week number of year, with Sunday as first day of week (00..53)
      %V   ISO week number, with Monday as first day of week (01..53)
      %w   day of week (0..6); 0 is Sunday
      %W   week number of year, with Monday as first day of week (00..53)
      %x   locale's date representation (e.g., 12/31/99)
      %X   locale's time representation (e.g., 23:13:48)
      %y   last two digits of year (00..99)
      %Y   year
      %z   +hhmm numeric timezone (e.g., -0400)
      %:z  +hh:mm numeric timezone (e.g., -04:00)
      %::z  +hh:mm:ss numeric time zone (e.g., -04:00:00)
      %:::z  numeric time zone with : to necessary precision (e.g., -04, +05:30)
      %Z   alphabetic time zone abbreviation (e.g., EDT)

使用Linux date命令实例：

如果不指定选项，date命令将显示当前系统日期和时间，包括星期几，月份，时间，时区和年份：

$ date
    Fri Sep 14 12:00:48 CST 2018

将当前时间按照'%Y-%m-%d %H:%M:%S'格式输出:

$ echo `date +'%Y-%m-%d %H:%M:%S'`
    2018-09-14 13:38:42

指定-d选项，date命令将显示指定的特定时间：

$ date -d "1974-01-04"
    Fri Jan  4 00:00:00 CST 1974

通过在格式字符串前面加上加号，date可是显示多种格式 ：

$ date +"Week number: %V Year: %y"
    Week number: 37 Year: 18

输出格式字符串，每个格式标记由其值替换。 ％V是显示当前周数的格式选项，％y表示年份的最后两位数。

确定给定日期是周几：

$ date -d "1974-01-04" +"%A"
    Friday

将当前时间按指定year-month-day格式输出：

$ echo `date "+%Y-%m-%d"`
    2018-09-14
    $ echo `date +%Y-%m-%d`
    2018-09-14

将当前时间往前推30天的日期，按指定year-month-day格式输出：

$ echo `date -d "-30 day" "+%Y-%m-%d"`
    2018-08-15

取当前时间前一天作为截止日期，截止日期往前推90天作为起始日期：

$ end_time=`date -d "-1 day" "+%Y-%m-%d"`
    $ start_time=`date -d "$end_time -90 day" "+%Y-%m-%d"`
    $ echo $start_time
    2018-06-15

参考：[https://www.linode.com/docs/tools-reference/tools/use-the-date-command-in-linux/\#formatting-options][https_www.linode.com_docs_tools-reference_tools_use-the-date-command-in-linux_formatting-options]

[https_www.linode.com_docs_tools-reference_tools_use-the-date-command-in-linux_formatting-options]: https://www.linode.com/docs/tools-reference/tools/use-the-date-command-in-linux/#formatting-options