Change a file's time stamp.
touch [options] files
-c stops touch from creating a file that does not exist.
-d time uses the specified time.
-r file uses the time stamp from the specified file.
-t MMDDhhmm[[CC]YY][.ss] uses the specified date and time.
The touch command lets you change the date and time of the last modification of a file (this information is stored with the file). If you use touch without any options, the current date and time are used as the time stamp for the file. If the specified file does not exist, touch creates a new file of size 0 bytes.