In Linux every single file is associated with timestamps, and every file stores the information of last access time, last modification time and last change time. So, whenever we create new file, access or modify an existing file, the timestamps of that file automatically updated.
Linux Touch Command Examples
In this article we will cover some useful practical examples of Linux touch command. The touch command is a standard program for Unix/Linux operating systems, that is used to create, change and modify timestamps of a file. Before heading up for touch command examples, please check out the following options.
Touch Command Options
- -a, change the access time only
- -c, if the file does not exist, do not create it
- -d, update the access and modification times
- -m, change the modification time only
- -r, use the access and modification times of file
- -t, creates a file using a specified time
1. How to Create an Empty File
The following touch command creates an empty (zero byte) new file called sheena.
# touch sheena
2. How to Create Multiple Files
By using touch command, you can also create more than one single file. For example the following command will create 3 files named, sheena, meena and leena.
# touch sheena meena leena
3. How to Change File Access and Modification Time
To change or update the last access and modification times of a file called leena, use the -a option as follows. The following command sets the current time and date on a file. If the leena file does not exist, it will create the new empty file with the name.
# touch -a leena
The most popular Linux commands such as find command and ls command uses timestamps for listing and finding files.
4. How to Avoid Creating New File
Using -c option with touch command avoids creating new files. For example the following command will not create a file called leena if it does not exists.
# touch -c leena
5. How to Change File Modification Time
If you like to change the only modification time of a file called leena, then use the -m option with touch command. Please note it will only updates the last modification times (not the access times) of the file.
# touch -m leena
6. Explicitly Set the Access and Modification times
You can explicitly set the time using -c and -t option with touch command. The format would be as follows.
# touch -c -t YYDDHHMM leena
For example the following command sets the access and modification date and time to a file leena as 17:30 (17:30 p.m.) December 10 of the current year (2012).
# touch -c -t 12101730 leena
Next verify the access and modification time of file leena, with ls -l command.
# ls -l total 2 -rw-r--r--. 1 root root 0 Dec 10 17:30 leena
7. How to Use the time stamp of another File
The following touch command with -r option, will update the time-stamp of file meena with the time-stamp of leena file. So, both the file holds the same time stamp.
# touch -r leena meena
8. Create a File using a specified time
If you would like to create a file with specified time other than the current time, then the format should be.
# touch -t YYMMDDHHMM.SS tecmint
For example the below command touch command with -t option will gives the tecmint file a time stamp of 18:30:55 p.m. on December 10, 2012.
# touch -t 201212101830.55 tecmint
We’ve almost covered all the options available in the touch command for more options use “man touch“. If we’ve still missed any options and you would like to include in this list, please update us via comment box.
Source: tecmint.com
