touch(1) is used to change the timestamp on a file. You can change access timestamps and modification timestamps with this command. If the file specified does not exist, touch will create a zero length file with the name specified. To mark a file with the current system time, you would issue this command:
$ touch file1 |
There are several options for touch, including options to specify which timestamp to modify, the time to use, and many more. The online manual page discusses these in detail.