How to use Linux touch command

1. Introduction to touch command

This command can be used to change the time attributes of a file or directory, including access time and modification time. If the file does not exist, a new file is created. What we usually use most is to create an empty file through touch. In fact, the atime and mtime of the file can be modified through the touch command, so the real access time and modification time of the file can be modified. We also need to do this when troubleshooting system abnormalities. Make comprehensive decisions based on factors such as logs and historical commands.

2. Usage examples

1. Get command help

[root@s145]~# touch --help

2. Check the command version

[root@s145]~# touch --version
touch (GNU coreutils) 8.22
…

3. Create an empty file

If the file does not exist, use the touch command to create an empty file by default.

4. Update atime, mtime, and ctime

Use the touch command. If the file exists, update atime, mtime, and ctime to the current time.

5. -a updates atime and ctime

Use the -a parameter. When touching the file, if the file exists, only atime and ctime will be updated to the current time.

6. -m parameter to modify mtime

Use the -m parameter. When touching a file, only mtime and ctime will be updated to the current time if the file exists.

7. The -d parameter will modify the atime, mtime, and ctime of the file according to the settings.

Use the option -d "3 years ago" of the touch command. Set the three timestamps of the file to 3 years ago.

8. -t parameter to modify atime and mtime

Use touch -t "[[CC]YY] MMDDhhmm[.ss]"Modify the atime and mtime of the file

9. Use the -at parameter to only modify the atime

If you only want to update the atime, you can use - at combination parameters.

10. Use the -mt parameter to only modify mtime

If you only want to update mtime, you can use the -mt combination parameter.

11. The -r parameter modifies the file time attribute to another file time attribute.

Use the touch command and specify the file1 file as a reference. You can change the file2 file The time attribute value of is updated to the same value as file1. The specific command is: touch -r file1 file2.

12. -h updates the time attribute of the soft link

The touch command updates the time attribute of the real file by default. If you need to update the time of the soft link, Attribute, you need to use the -h parameter.

3. Usage syntax and parameter description

1. Usage syntax

Usage: touch [OPTION]… FILE&hellip ;

2. Parameter description

Parameter	Parameter description
- a	Change the file's read time record.
-c	If the destination file does not exist, a new file will not be created. Same effect as --no-create.
-d	Set the time and date in various formats.
-f	is not used and is reserved for compatibility with other unix systems.
-h	Affects each symlink, not any referenced file (only useful on systems where symlink timestamps can be changed)
-m	Change the modification time record of the file.
-r	Use the time record of the reference file, which has the same effect as --file.
-t	Set the time record of the file, the format is the same as the date command.
–help	Lists the command format.
–version	List version information.

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