The date usage of the shell

#man Date can see the Help file for date
#date Get the current time
#date-D " -1week" +%y%m%d access to the Sunday period (day,month,year,hour)
#date--date= " -24 hour" +%y%m%d ditto
date_now= ' date+%s ' shell script assigns variable values
%%% OUTPUT% symbol
%a the current domain's weekday abbreviation (Sun ... Sat)
%A the current domain for the full week (Sunday. Saturday)
%B the month abbreviation for the current field. DEC)
%B the full month name of the current domain (January. December)
Default time format for current field in%c (Sat Nov 12:02:33 EST 1989)
%c N Hundred years [00-99]
%d two-bit days (01..31)

%d Short time Format (MM/DD/YY)

%e Short Format Day (1..31)

%F file time format same as%y-%m-%d

%h Same as%b

%H 24-hour hours (00..23)

%I 12-hour hours (01..12)

%j Day of the Year (001..366)

%k Short Form 24 hour (0..23)

%l Short Form 12 Hour (1..12)

%m Two-digit month (01..12)

%m double digit minute (00..59)

%n Line Change

%N One-zero seconds (000000000..999999999)

%p Upper afternoon indication of the current field in uppercase (blank in many locales)

%P on the upper PM of the current field of lowercase (blank in many locales)

%r 12-hour Time representation (time: minutes: seconds, double digits) times, 12-hour (Hh:mm:ss [ap]m)
%R 24-hour time representation (time: minutes, double digits) times, 24-hour (hh:mm)
%s from base time 1970-01-01 00:00:00 to current time seconds (a GNU extension)
%s Dual-digit seconds second (00..60);
%t horizontal tab (tab)
%T 24-hour time representation (HH:MM:SS)
%u number of weeks represented (starting from Monday 1-7)
%u the first weeks of the year Sunday as the beginning (00..53)
%V the first few weeks of the year Monday as the beginning (01..53)
%w Day of the week of Sunday as the beginning (0..6)
%w the first few weeks of the year Monday as the beginning (00..53)
%x Local date format (MM/DD/YY)
%x local time format (%h:%m:%s)
%y Two-bit year (00..99)
%Y year (1970 ...)
Example: Write a shell script to calculate how many days from your birthday.

Read-p "Input your Birthday (YYYYMMDD):" Date1
m= ' date--date= "$date 1" +%m ' #得到生日的月 d= ' date--date= '
$date 1 "+%d" #得到生日的日
date_now= ' date+%s ' #得到当前时间的秒值
y= ' date +%y ' #得到当前时间的年
birth= ' date--date= ' $y $m$d ' +%s ' #得到今年的生日日期 The second value
internal=$ (($birth-$date _now)) #计算今日到生日日期的间隔时间
if ["$internal"-lt "0"]; then #判断今天的生日是否已过
birth= ' d Ate--date= "$ (($y + 1)) $m $d" +%s "#得到明天的生日日期秒值
internal=$ (($birth-$date _now)) #计算今天到下一个生日的间隔时间
fi
echo" Thereis: $ ((einternal/60/60/24)) days. "#输出结果, second conversion to day

To create a file name with the current time

mkdir ' date+%y%m%d '

Backup takes time as the filename

Tar cvf./htdocs ' date +%y%m%d '. Tar./*

How does the date command get the dates of the previous week?

Lastmonth= ' Date+%y-%m--date= '-1 month "'"-01 ";

The awk-v is then passed as a parameter in a simple point.

#date-D " -1week" "+%y%m%d%A"

Or: #date-D "Last week" +%y%m%d

Extrapolate: Date order obtained the day before yesterday, tomorrow, the day after, last month, next month

Date-d "-2 Day" "+%y%m%d%A" or date--date= "2 days Ago" "+%y%m%d%A"

Date-d "-1 Day" "+%y%m%d%A" or date--date= "1 day Ago" "+%y%m%d%A"

Date-d "1 Day" "+%y%m%d%A"

Date-d "2 Day" "+%y%m%d%A"

Date-d "-1 month" "+%y%m%d%A"

Date-d "1 Month" "+%y%m%d%A"

Echo ' date-d '-1 month "" +%y-%m-%d%x "

There are other uses:

Date+%s can get the time stamp of Unix;

Known timestamp, ask for current date
Date--date= "19700101 +$ (((' Date +%s ') + (8*60*60))) sec" +%y%m%d ""%h:%m:%s
PS: Starting from January 01, 1970, +$ (((' Date +%s ') + (8*60*60)) The SEC indicates how many seconds have passed, in which (8*60*60) represents 8 hours, time zone problem, China time and world time difference 8 hours.

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