touch
[options] [date] filesFor one or more files, update the access time and modification timestamp to the current time and date, or update to the optional date. date is a date and time in the format mmddhhmm[yy]. touch is useful in forcing other commands to handle files a certain way; e.g., the operation of make, and sometimes find, relies on a file's access and modification times.
-a
Update only the access time.
-c
Do not create nonexistent files.
-m
Update only the modification time.
-r
fileUse the access and/or modification times of file instead of the current time. Solaris only.
-t
timeUse the time as provided by time, which has the form [[cc]yy]mmddhhmm[.
ss]. Solaris only.