A Linux touch command every day

Linux touch commands are not commonly used, and are generally used when using make, to modify file timestamps, or to create a new file that does not exist.

There are three timestamps of the file (available stat Viewing):

Access time: Atime, reading the contents of a file

Modify Time: Modified, Mtime, change file contents (data)

Change time: Changing times, ctime, meta data changes

1. command format:

Touch [options] ... File ...

2. Command parameters:

-a or--time=atime or--time=access or--time=use only Change access timestamp

- C or--no-create do not create any documents

- m or--time=mtime or--time=modify only change the modified timestamp

-T uses the specified date time instead of the current time

3. Command function:

The touch command parameter changes the date time of the document or directory, including access time and change time.

4. Examples of use:

instance One: Create a file that does not exist

Command:

Touch Log.txt

Output:

[begin] 2015/12/23 13:35:22[[email protected] ~]#  lsanaconda-ks.cfg  install.log  install.log.syslog  text[[email  PROTECTED] ~]# TOUCH LOG.TXT[[EMAIL PROTECTED] ~]# LLTOTAL 64-RW-------.  1 root root  3328 dec 19 05:42 anaconda-ks.cfg-rw-r--r--.  1  root root 39935 dec 19 05:42 install.log-rw-r--r--.  1 root  Root  9154 dec 19 05:39 install.log.syslog-rw-r--r--  1 root  root     0 dec 23 05:36 log.txtdrwxr-xr-x  3  root root  4096 dec 22 16:09 text[end] 2015/12/23 13:36:02 

 

[Begin] 2015/12/23 14:07:07[[email protected] ~]# stat text  file:   ' text '   Size: 4096      Blocks: 8           io block: 4096   directorydevice: 802h /2050dinode: 401425      links: 3access:  (0755/drwxr-xr-x)    Uid:  (    0/    root)    Gid:  (     0/    root) access: 2015-12-22 16:10:05.975041002 - 0800modify: 2015-12-22 16:09:57.538043360 -0800change: 2015-12-22 16:09:57.538043360  -0800[[email protected] ~]# datewed dec 23 06:07:31 pst 2015[[ email protected] ~]# touch -a text[[email protected] ~]# stat  text  file:  ' text '   size: 4096      blocks: 8           io block: 4096   directorydevice: 802h/2050dinode:  401425      Links: 3Access:  (0755/drwxr-xr-x)   uid:   (    0/    root)    Gid:  (     0/    root) access: 2015-12-23 06:07:51.421979327 -0800modify:  2015-12-22 16:09:57.538043360 -0800change: 2015-12-23 06:07:51.421979327 -0800[[email  protected] ~]# datewed dec 23 06:08:07 pst 2015[end] 2015/12/23  14:08:00

Description: The access timestamp for text was changed from 2015-12-22 16:10:05 to 2015-12-23 06:07:51, synchronized with the time of date, because the text metadata changed, so the change time of text changed.

example Three: Do not create any documents

Command:

Touch-c text

Output :

[BEGIN] 2015/12/23 14:13:05[[email protected] ~]# [[email protected] ~]# lsanaconda-ks.cfg install.log install.log.syslo G Log.txt text[[email protected] ~]# touch-c text1[[email protected] ~]# lsanaconda-ks.cfg install.log install.log.sy Slog Log.txt Text[end] 2015/12/23 14:13:29

Example four:

Command:

Touch-m text

output:

[Begin] 2015/12/23 14:20:51[[email protected] ~]# stat text  file:   ' text '   Size: 4096      Blocks: 8           io block: 4096   directorydevice: 802h /2050dinode: 401425      links: 3access:  (0755/drwxr-xr-x)    Uid:  (    0/    root)    Gid:  (     0/    root) access: 2015-12-23 06:21:14.894978504 - 0800modify: 2015-12-22 16:09:57.538043360 -0800change: 2015-12-23 06:07:51.421979327  -0800[[email protected] ~]# touch -m text[[email protected] ~]#  stat text/  file:  ' text/'   Size: 4096       blocks: 8          io block: 4096   directorydevice:  802h/2050dinode: 401425      links: 3access:  (0755/drwxr-xr-x)   Uid:  (    0/    root)    Gid:  (     0/    root) access: 2015-12-23 06:21:14.894978504 - 0800modify: 2015-12-23 06:21:53.599978353 -0800change: 2015-12-23 06:21:53.599978353  -0800[end] 2015/12/23 14:21:53

Description: The modified timestamp of text was changed from 2015-12-22 16:09:57 to 2015-12-23 06:21:53, synchronized with the time of date, because the text metadata changed, so the change time of text changed.

Example five: Setting the access timestamp and modification timestamp of the file

Command:

touch-t 201608301830.55 text 201608301830.55 refers to August 30, 2016 18:30 55 seconds

[Begin] 2015/12/23 14:37:31[[email protected] ~]# stat text  file:   ' text '   Size: 4096      Blocks: 8           io block: 4096   directorydevice: 802h /2050dinode: 401425      links: 3access:  (0755/drwxr-xr-x)    Uid:  (    0/    root)    Gid:  (     0/    root) access: 2015-12-23 06:37:31.563977563 - 0800modify: 2015-12-23 06:37:31.563977563 -0800change: 2015-12-23 06:37:31.563977563  -0800[[email protected] ~]# touch -t 201608301830.55 text[[email  protected] ~]# stat text  file:  ' text '   Size: 4096       blocks: 8          io block: 4096    Directorydevice: 802h/2050dinode: 401425      links: 3access:   (0755/drwxr-xr-x)   Uid:  (    0/    root)     Gid:  (    0/    root) access: 2016-08-30  18:30:55.000000000 -0700modify: 2016-08-30 18:30:55.000000000 -0700change: 2015-12-23  06:38:23.520977454 -0800[end] 2015/12/23 14:38:24

Description: The access and modification timestamp for text was changed from 2015-12-23 06:37:31 to 2016-08-30 18:30:55 because it only sets the timestamp of text, so the metadata for text has not changed, so changing the timestamp does not change.

A Linux touch command every day