Linux time zone and time modification

Modify the time zone: 1 & gt; find the corresponding time zone file/usr/share/zoneinfo/Asia/Shanghai and replace the current/etc/localtime file with this file. Or find the server that you think is standard time, and then # scproot@xxx.xxx.xxx.xxx:/etc/localtime/etc/localtim...

Modify the time zone:
1>
Find the corresponding time zone file/usr/share/zoneinfo/Asia/Shanghai
Replace the current/etc/localtime file with this file.
Or find the server that you think is the standard time, and then
# Scp root@xxx.xxx.xxx.xxx:/etc/localtime
2>
Modify the/etc/sysconfig/clock file:
ZONE = "Asia/Shanghai"
UTC = false
ARC = false

Modify date and time
1>
Use date to modify the date and time
# Date-s 08/24/2006
# Date-s 13:02:00
2>
Synchronizes the BIOS clock and forces the system time to be written to CMOS.
# Clock-w

In addition, use # hwclock-r to view Bois time
# Tzselect can be used to interactively modify the time zone

Linux system time zone modification
1. view the current time zone

# Vi/etc/sysconfig/clock
2. modify the time zone

Method (1) # tzselect method (2 Limited to RedHat Linux and CentOS) # timeconfig
3. copy the corresponding time zone file to replace the default time zone of the system.

# Cp/usr/share/zoneinfo/$ Main time zone/$ time zone/etc/localtime: # cp/usr/share/zoneinfo/Asia/Shanghai/etc/localtime
4. write the current time into the BIOS for permanent effect (to prevent failure after restart)

# Hwclock

Generally, two methods are used to obtain the timestamp in the inux shell. one is to directly call the system variable; the other is to obtain the timestamp using a pure shell script. The example is as follows:

1. directly call system variables

Obtain the current period: date + % Y % m % d' or date + % F

Get the period of yesterday: 'Date-d yesterday + % Y % m % d'

Get date of the day before yesterday: 'Date-d-2day + % Y % m % d'

And so on, for example, get the date 10 days ago: 'Date-d-10day + % Y % m % d'

Note that there are spaces in the middle.

2. implement it by using shell. the following example shows the shell that calculates the date of yesterday when the current day is known.

Startdate = 'Date'
D1 = 'Date' + % Y % m % d''
If test! "$1" = ""
Then
D1 = $1
Fi
Echo "today is ${d1 }"
Yesterday ()
{
YEAR = 'expr substr "$ {d1}" 1 4'
MONTH = 'expr substr "$ {d1}" 5 2'
DAY = 'expr substr "$ {d1}" 7 2'
If [$ DAY-eq 1]
Then
If [$ MONTH-eq 1]
Then
YEAR = 'expr $ YEAR-1'
MONTH = 12
Else
MONTH = 'expr $ MONTH-1'
Fi
DAY = 'echo \ 'Cal $ MONTH $ YEAR \ '| tail-n1 | awk' {print $ NF }''
Else
DAY = 'expr $ DAY-1'
Fi
D2 = 'echo "$ YEAR $ MONTH $ DAY" | awk '{if (length ($2) = 1) $2 = 0 $2; if (length ($3) = 1) $3 = 0 $3; printf "% s", $1, $2, $3 }''
}
Yesterday
Echo "yesterday IS ${d2 }"



Author: jsczxy2