Linux file directory time update touch command usage

Name: Touch
Use Rights: All users
How to use:
Touch [-acfm]
[R Reference-file] [--file=reference-file]
[-t MMDDHHMM[[CC]YY][.SS]]
[-D Time] [--date=time] [--time={atime,access,use,mtime,modify}]
[--no-create] [--help] [--version]
File1 [File2 ...]
Description
The touch command changes the time record of the file. Ls-l can display the time record of the file.
Parameters:
A change the read time record of the file.
M changes the file's modification time record.
c If the destination file does not exist, no new files will be created. The same as the--no-create effect.
F is not used and is reserved for compatibility with other UNIX systems.
R use the reference file's time record as--file.
D Set the time and date, you can use a variety of different formats.
T sets the file's time record in the same format as the date instruction.
--no-create will not create new files.
--HELP lists the instruction formats.
--version lists version messages.
Use Example:
Instance one: Creating a file that does not exist
Command:
Touch Log2012.log Log2013.log
Output:
[Root@localhost test]# Touch Log2012.log Log2013.log
[Root@localhost test]# LL
-rw-r--r--1 root 0 10-28 16:01 log2012.log
-rw-r--r--1 root 0 10-28 16:01 log2013.log
If Log2014.log does not exist, the file is not created
[Root@localhost test]# touch-c Log2014.log
[Root@localhost test]# LL
-rw-r--r--1 root 0 10-28 16:01 log2012.log
-rw-r--r--1 root 0 10-28 16:01 log2013.log
Instance two: Update Log.log time and Log2012.log time stamp the same
Command:
Touch-r Log.log Log2012.log
Output:
[Root@localhost test]# LL
-rw-r--r--1 root 0 10-28 16:01 log2012.log
-rw-r--r--1 root 0 10-28 16:01 log2013.log
-rw-r--r--1 root 0 10-28 14:48 log.log
[Root@localhost test]# touch-r log.log log2012.log
[Root@localhost test]# LL
-rw-r--r--1 root 0 10-28 14:48 log2012.log
-rw-r--r--1 root 0 10-28 16:01 log2013.log
-rw-r--r--1 root 0 10-28 14:48 log.log

Example three: Set the timestamp of a file

Command:
Touch-t 201211142234.50 Log.log
Output:
[Root@localhost test]# LL
-rw-r--r--1 root 0 10-28 14:48 log2012.log
-rw-r--r--1 root 0 10-28 16:01 log2013.log
-rw-r--r--1 root 0 10-28 14:48 log.log
[Root@localhost test]# touch-t 201211142234.50 log.log
[Root@localhost test]# LL
-rw-r--r--1 root 0 10-28 14:48 log2012.log
-rw-r--r--1 root 0 10-28 16:01 log2013.log
-rw-r--r--1 root 0 2012-11-14 log.log

Description

The

-t  time uses the value of a specified timestamp as the new value for the appropriate timestamp for the specified file. The time here is defined as a decimal number in the form:     
  [cc]yy]mmddhhmm[. ss]    
  Here, CC is the first two digits of the year, the number of centuries, and yy is the last two digits of the year, the number of years in a century. If the value of CC is not given, then touch   will limit the number of years Ccyy to 1969--2068. MM is the number of months, DD for days will be the number of years Ccyy limited within the 1969--2068. MM is the number of months, DD is the number of days, HH for hours (several), MM for minutes, SS for seconds. The set of seconds here is 0--61 so that you can handle leap seconds. These numbers consist of a time in the specified time zone of the environment variable TZ. Due to the limitations of the system, the time earlier than January 1, 1970 is wrong.