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Linux Touch Command

The touch command allows us to update the timestamps on existing files and directories as well as creating new, empty files.

In this guide, we will show you how to use the touch command through practical examples and detailed explanations of the most common command options.

Linux Files Timestamps

Before going into how to use the touch command, let’s start by reviewing the file timestamps in Linux.

A file in Linux has three timestamps:

  • atime (access time) - The last time the file was accessed/opened by some command or application such as cat, vim or grep.
  • mtime (modify time) - The last time the file’s content was modified.
  • ctime (change time) - The last time the file’s attribute or content was changed. The attribute includes file permissions, file ownership or file location.

To display the file status including the timestamps you can use the stat command.

stat file_name

How to use the touch command

In it’s simplest form when used without any options, if the file name specified as argument doesn’t exist touch will create a new file.

If the file already exist touch will change the file last access and modification times to the current time.

For example, if the file file1 doesn’t exist the following command will create it otherwise it will change its timestamps:

touch file1

To create od modify multiple files or change at once, specify the file names as arguments:

touch file1 file2 file3

If you don’t want the touch command to create new files, use the -c (--no-create) option.

For example, the following command will change the file file1 timestamps if it exist, otherwise it will do nothing:

touch -c file1

Changing only access or modification times

By default if no option is used touch will update the file last access and modification times to the current time. By using the -a and -m options, you can change only one of these timestamps.

Change only the access time

Use the -a option to change only the file’s access time:

touch -a file1

Change only the modify time

Use the -m option to change the file’s modify time:

touch -m file1

When changing the modify time, the change time will be also updated.

Setting specific timestamps

The touch command also allow us to update or create a file with specific time other than the current time.

Use the -d (--date=) option to specify a date string and use it instead of current time.

For example, to change both the last access and modification times of file1 to 1 June 2018 11:02 you would use the following command:

touch -d '1 June 2018 11:02' file1

The date string needs to be enclosed in single quotes.

You can also provide a partial date-time string to the touch command. For example providing only the date, automatically changes the year to the current one:

touch -d '12 June' file1

Use the -t option to specify a timestamp and use it instead of current time. The timestamp argument needs to be be in the following format:

use [[CC]YY]MMDDhhmm[.ss]

For example, the following command will set last access and modification times of file1 to 1 June 11:02 of the current year.

touch -t 12061102 file1

Using the timestamp of another file

The -r (--reference=) option allow us to specify a reference file and use its time stamps instead of current time.

For example, the following command will tell touch to use the times of file1 for file2:

touch -r file1 file2

By default, if you use a touch command on a symbolic link it will change the timestamps of its referenced file.

Use the -h (--no-dereference) to modify the timestamp of the symlink.

For example, to change the timestamps of the symbolic link symlink1 you would use:

touch -h symlink1

Conclusion

By now you should have a good understanding of how to use the Linux touch command.