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.
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.
The following touch command creates an empty (zero byte) new file called file1.
# touch file1
By using touch command, you can also create more than one single file. For example the following command will create 3 files named, file1, file2 and file3.
# touch file1 file2 file3
To change or update the last access and modification times of a file called file3, use the -a option as follows. The following command sets the current time and date on a file. If the file3 file does not exist, it will create the new empty file with the name.
# touch -a file3
Using -c option with touch command avoids creating new files. For example the following command will not create a file called file3 if it does not exists.
# touch -c file3
If you like to change the only modification time of a file called file3, 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 file3
You can explicitly set the time using -c and -t option with touch command. The format would be as follows.
# touch -c -t YYDDHHMM file3
For example the following command sets the access and modification date and time to a file file3 as 17:30 (17:30 p.m.) December 10 of the current year (2012).
# touch -c -t 12101730 file3
Next verify the access and modification time of file file3, with ls -l command.
# ls -l total 2 -rw-r--r--. 1 root root 0 Dec 10 17:30 file3
The following touch command with -r option, will update the time-stamp of file file2 with the time-stamp of file3 file. So, both the file holds the same time stamp.
# touch -r file3 file2
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 deexams
For example the below command touch command with -t option will gives the deexams file a time stamp of 18:30:55 p.m. on December 10, 2012.
# touch -t 201212101830.55 deexams
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.
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