命令简介：
date 根据给定格式显示日期或设置系统日期时间。print or set the system date and time
指令所在路径：/bin/date
命令语法：
date [OPTION]... [+FORMAT]
date [-u|--utc|--universal] [MMDDhhmm[[CC]YY][.ss]]
命令参数：
参数
描述
-d
显示字符串描述的时间
-f
显示DATEFILE文件中的每行时间
-r
显示文件的最后修改时间
-R
以RFC-2822兼容日期格式显示时间
-rfc-2822
以RFC-2822兼容日期格式显示时间
-s
设置时间为string
-u
显示或设定为Coordinated Universal Time时间格式
--help
显示date命令的帮助信息
--version
显示date命令的版本信息
Format参数格式
要说写这位程序的 David MacKenzie老兄，真是事无巨细啊，居然整了这么多格式参数，佩服佩服。
参数
描述
%%
显示字符%
%a
星期几的缩写(Sun..Sat)
%A
星期几的完整名称（Sunday...Saturday）
%b
月份的缩写(Jan..Dec)
%B
月份的完整名称(January..December)
%c
日期与时间。只输入date指令也会显示同样的结果
%C
世纪(年份除100后去整) [00-99]
%d
日期(以01-31来表示)。
%D
日期(含年月日)。
%e
一个月的第几天 ( 1..31)
%F
日期，同%Y-%m-%d
%g
年份(yy)
%G
年份(yyyy)
%h
同%b
%H
小时(00..23)
%I
小时(01..12)
%j
一年的第几天(001..366)
%k
小时( 0..23)
%l
小时( 1..12)
%m
月份(01..12)
%M
分钟(00..59)
%n
换行
%N
纳秒(000000000..999999999)
%p
AM or PM
%P
am or pm
%r
12小时制时间(hh:mm:ss [AP]M)
%R
24小时制时间(hh:mm)
%s
从00:00:00 1970-01-01 UTC开始的秒数
%S
秒(00..60)
%t
制表符
%T
24小时制时间(hh:mm:ss)
%u
一周的第几天(1..7); 1 表示星期一
%U
一年的第几周，周日为每周的第一天(00..53)
%V
一年的第几周，周一为每周的第一天 (01..53)
%w
一周的第几天 (0..6); 0 代表周日
%W
一年的第几周，周一为每周的第一天(00..53)
%x
日期(mm/dd/yy)
%X
时间(%H:%M:%S)
%y
年份(00..99)
%Y
年份 (1970…)
%z
RFC-2822 风格数字格式时区(-0500)
%Z
时区(e.g., EDT), 无法确定时区则为空
使用示例：
1： 查看date命令帮助信息
1: [root@DB-Server ~]# date --help 2: 3: Usage: date [OPTION]... [+FORMAT] 4: 5: or: date [-u|--utc|--universal] [MMDDhhmm[[CC]YY][.ss]] 6: 7: Display the current time in the given FORMAT, or set the system date. 8: 9: -d, --date=STRING display time described by STRING, not `now' 10: 11: -f, --file=DATEFILE like --date once for each line of DATEFILE 12: 13: -r, --reference=FILE display the last modification time of FILE 14: 15: -R, --rfc-2822 output date and time in RFC 2822 format 16: 17: --rfc-3339=TIMESPEC output date and time in RFC 3339 format. 18: 19: TIMESPEC=`date', `seconds', or `ns' for 20: 21: date and time to the indicated precision. 22: 23: -s, --set=STRING set time described by STRING 24: 25: -u, --utc, --universal print or set Coordinated Universal Time 26: 27: --help display this help and exit 28: 29: --version output version information and exit 30: 31: FORMAT controls the output. The only valid option for the second form 32: 33: specifies Coordinated Universal Time. Interpreted sequences are: 34: 35: %% a literal % 36: 37: %a locale's abbreviated weekday name (e.g., Sun) 38: 39: %A locale's full weekday name (e.g., Sunday) 40: 41: %b locale's abbreviated month name (e.g., Jan) 42: 43: %B locale's full month name (e.g., January) 44: 45: %c locale's date and time (e.g., Thu Mar 3 23:05:25 2005) 46: 47: %C century; like %Y, except omit last two digits (e.g., 21) 48: 49: %d day of month (e.g, 01) 50: 51: %D date; same as %m/%d/%y 52: 53: %e day of month, space padded; same as %_d 54: 55: %F full date; same as %Y-%m-%d 56: 57: %g last two digits of year of ISO week number (see %G) 58: 59: %G year of ISO week number (see %V); normally useful only with %V 60: 61: %h same as %b 62: 63: %H hour (00..23) 64: 65: %I hour (01..12) 66: 67: %j day of year (001..366) 68: 69: %k hour ( 0..23) 70: 71: %l hour ( 1..12) 72: 73: %m month (01..12) 74: 75: %M minute (00..59) 76: 77: %n a newline 78: 79: %N nanoseconds (000000000..999999999) 80: 81: %p locale's equivalent of either AM or PM; blank if not known 82: 83: %P like %p, but lower case 84: 85: %r locale's 12-hour clock time (e.g., 11:11:04 PM) 86: 87: %R 24-hour hour and minute; same as %H:%M 88: 89: %s seconds since 1970-01-01 00:00:00 UTC 90: 91: %S second (00..60) 92: 93: %t a tab 94: 95: %T time; same as %H:%M:%S 96: 97: %u day of week (1..7); 1 is Monday 98: 99: %U week number of year, with Sunday as first day of week (00..53) 100: 101: %V ISO week number, with Monday as first day of week (01..53) 102: 103: %w day of week (0..6); 0 is Sunday 104: 105: %W week number of year, with Monday as first day of week (00..53) 106: 107: %x locale's date representation (e.g., 12/31/99) 108: 109: %X locale's time representation (e.g., 23:13:48) 110: 111: %y last two digits of year (00..99) 112: 113: %Y year 114: 115: %z +hhmm numeric timezone (e.g., -0400) 116: 117: %:z +hh:mm numeric timezone (e.g., -04:00) 118: 119: %::z +hh:mm:ss numeric time zone (e.g., -04:00:00) 120: 121: %:::z numeric time zone with : to necessary precision (e.g., -04, +05:30) 122: 123: %Z alphabetic time zone abbreviation (e.g., EDT) 124: 125: By default, date pads numeric fields with zeroes. 126: 127: The following optional flags may follow `%': 128: 129: - (hyphen) do not pad the field 130: 131: _ (underscore) pad with spaces 132: 133: 0 (zero) pad with zeros 134: 135: ^ use upper case if possible 136: 137: # use opposite case if possible 138: 139: After any flags comes an optional field width, as a decimal number; 140: 141: then an optional modifier, which is either 142: 143: E to use the locale's alternate representations if available, or 144: 145: O to use the locale's alternate numeric symbols if available. 146: 147: Report bugs to <bug-coreutils@gnu.org>. 148: 1: [root@DB-Server ~]# man date 2: 3: DATE(1) User Commands DATE(1) 4: 5: NAME 6: 7: date - print or set the system date and time 8: 9: SYNOPSIS 10: 11: date [OPTION]... [+FORMAT] 12: 13: date [-u|--utc|--universal] [MMDDhhmm[[CC]YY][.ss]] 14: 15: DESCRIPTION 16: 17: Display the current time in the given FORMAT, or set the system date. 18: 19: -d, --date=STRING 20: 21: display time described by STRING, not ‘now’ 22: 23: -f, --file=DATEFILE 24: 25: like --date once for each line of DATEFILE 26: 27: -r, --reference=FILE 28: 29: display the last modification time of FILE 30: 31: -R, --rfc-2822 32: 33: output date and time in RFC 2822 format 34: 35: --rfc-3339=TIMESPEC 36: 37: output date and time in RFC 3339 format. TIMESPEC=‘date’, ‘seconds’, or ‘ns’ for date and time to the indicated precision. 38: 39: -s, --set=STRING 40: 41: set time described by STRING 42: 43: -u, --utc, --universal 44: 45: print or set Coordinated Universal Time 46: 47: --help display this help and exit 48: 49: --version 50: 51: output version information and exit 52: 53: FORMAT controls the output. The only valid option for the second form specifies Coordinated Universal Time. Interpreted sequences are: 54: 55: %% a literal % 56: 57: %a locale’s abbreviated weekday name (e.g., Sun) 58: 59: %A locale’s full weekday name (e.g., Sunday) 60: 61: %b locale’s abbreviated month name (e.g., Jan) 62: 63: %B locale’s full month name (e.g., January) 64: 65: %c locale’s date and time (e.g., Thu Mar 3 23:05:25 2005) 66: 67: %C century; like %Y, except omit last two digits (e.g., 21) 68: 69: %d day of month (e.g, 01) 70: 71: %D date; same as %m/%d/%y 72: 73: %e day of month, space padded; same as %_d 74: 75: %F full date; same as %Y-%m-%d 76: 77: %g last two digits of year of ISO week number (see %G) 78: 79: %G year of ISO week number (see %V); normally useful only with %V 80: 81: %h same as %b 82: 83: %H hour (00..23) 84: 85: %I hour (01..12) 86: 87: %j day of year (001..366) 88: 89: %k hour ( 0..23) 90: 91: %l hour ( 1..12) 92: 93: %m month (01..12) 94: 95: %M minute (00..59) 96: 97: %n a newline 98: 99: %N nanoseconds (000000000..999999999) 100: 101: %p locale’s equivalent of either AM or PM; blank if not known 102: 103: %P like %p, but lower case 104: 105: %r locale’s 12-hour clock time (e.g., 11:11:04 PM) 106: 107: %R 24-hour hour and minute; same as %H:%M 108: 109: %s seconds since 1970-01-01 00:00:00 UTC 110: 111: %S second (00..60) 112: 113: %t a tab 114: 115: %T time; same as %H:%M:%S 116: 117: %u day of week (1..7); 1 is Monday 118: 119: %U week number of year, with Sunday as first day of week (00..53) 120: 121: %V ISO week number, with Monday as first day of week (01..53) 122: 123: %w day of week (0..6); 0 is Sunday 124: 125: %W week number of year, with Monday as first day of week (00..53) 126: 127: %x locale’s date representation (e.g., 12/31/99) 128: 129: %X locale’s time representation (e.g., 23:13:48) 130: 131: %y last two digits of year (00..99) 132: 133: %Y year 134: 135: %z +hhmm numeric timezone (e.g., -0400) 136: 137: %:z +hh:mm numeric timezone (e.g., -04:00) 138: 139: %::z +hh:mm:ss numeric time zone (e.g., -04:00:00) 140: 141: %:::z numeric time zone with : to necessary precision (e.g., -04, +05:30) 142: 143: %Z alphabetic time zone abbreviation (e.g., EDT) 144: 145: By default, date pads numeric fields with zeroes. The following optional flags may follow ‘%’: 146: 147: - (hyphen) do not pad the field _ (underscore) pad with spaces 0 (zero) pad with zeros ^ use upper case if possible # use opposite case if possible 148: 149: After any flags comes an optional field width, as a decimal number; then an optional modifier, which is either E to use the locale’s alternate representations if available, 150: 151: or O to use the locale’s alternate numeric symbols if available. 152: 153: ENVIRONMENT 154: 155: TZ Specifies the timezone, unless overridden by command line parameters. If neither is specified, the setting from /etc/localtime is used. 156: 157: AUTHOR 158: 159: Written by David MacKenzie. 160: 161: REPORTING BUGS 162: 163: Report bugs to <bug-coreutils@gnu.org>. 164: 165: COPYRIGHT 166: 167: Copyright ? 2006 Free Software Foundation, Inc. 168: 169: This is free software. You may redistribute copies of it under the terms of the GNU General Public License <http://www.gnu.org/licenses/gpl.html>. There is NO WARRANTY, to 170: 171: the extent permitted by law. 172: 173: SEE ALSO 174: 175: The full documentation for date is maintained as a Texinfo manual. If the info and date programs are properly installed at your site, the command 176: 177: info date 178: 179: should give you access to the complete manual. 180: 181: date 5.97 May 2011 DATE(1) 182:2：查看date命令的版本信息
1: [root@DB-Server ~]# date --version 2: 3: date (GNU coreutils) 5.97 4: 5: Copyright (C) 2006 Free Software Foundation, Inc. 6: 7: This is free software. You may redistribute copies of it under the terms of 8: 9: the GNU General Public License <http://www.gnu.org/licenses/gpl.html>. 10: 11: There is NO WARRANTY, to the extent permitted by law. 12: 13: Written by David MacKenzie. 14:3：运用-d参数
1: [root@DB-Server ~]# date -d now 2: 3: Thu Nov 14 22:52:45 PST 2013 4: 5: [root@DB-Server ~]# date -d 'next monday' 6: 7: Mon Nov 18 00:00:00 PST 2013 8: 9: [root@DB-Server ~]# date -d yesterday +%Y%m%d 10: 11: 20131113 12:4：显示文件中的时间
1: [root@DB-Server ~]# cat >date.txt 2: 3: 2013-11-17 10:54:00 4: 5: 2013-11-22 11:11:11 6: 7: [root@DB-Server ~]# more date.txt 8: 9: 2013-11-17 10:54:00 10: 11: 2013-11-22 11:11:11 12: 13: [root@DB-Server ~]# date -f date.txt 14: 15: Sun Nov 17 10:54:00 PST 2013 16: 17: Fri Nov 22 11:11:11 PST 2013 18:5：显示文件最后修改的时间
1: [root@DB-Server ~]# date -r install.log 2: 3: Fri Sep 6 11:31:15 PDT 2013 4:6：按各种格式显示当前日期时间
这个命令的格式参数实在是太多了，在此没有必要每一个参数都尝试一遍，大家可以对唱Format参数表，自己敲一敲命令实践一下。
1: 6.1 只显示当前日期的年份 2: 3: [root@DB-Server ~]# date +%Y 4: 5: 2013 6: 7: 6.2 只显示当前日期的月份 8: 9: [root@DB-Server ~]# date +%m 10: 11: 11 12: 13: 6.3 显示各种格式类型的日期 14: 15: [root@DB-Server ~]# date +%D 16: 17: 11/14/13 18: 19: [root@DB-Server ~]# date '+%Y-%m-%d' 20: 21: 2013-11-14 22: 23: [root@DB-Server ~]# date +%Y-%m-%d 24: 25: 2013-11-14 26: 27: [root@DB-Server ~]# date +%m/%d/%y 28: 29: 11/14/13 30: 31: [root@DB-Server ~]# date +%m/%d/%Y 32: 33: 11/14/2013 34: 35: ....... 36:7: 设置系统时间
1: [root@DB-Server ~]# date -s "2013-11-14 00:00:00" 2: 3: Thu Nov 14 00:00:00 PST 2013 作者： 潇湘隐者 出处： http://www.cnblogs.com/kerrycode/
