how does -f option of the date command works?

[abhinav4987]

Iam having trouble with -f option of date command, can someone please illustrate how does it works?

 

[tingo]

Here:

tingo@kg-core2$ date -f "%D" "06/29/00"
date: bind: Permission denied
date: settimeofday (timeval): Operation not permitted

I don't actually want to change the date on my machine, so I'm not running it as root. :-D
FWIW, the manual page for date(1) says you should look at strptime(3) to find out more about the format for the '-f' parameter, if you look at the strptime man page you will be directed to strftime(3), which has the format codes.

 

[abhinav4987]

okay ,
I saw %D is a specified date format. but what purpose does 06/29/00 serves?

 

[SirDice]

That's going to be the "new_date" that's being set.

 -f	     Use input_fmt as the format string	to parse the new_date provided
	     rather than using the default [[[[[cc]yy]mm]dd]HH]MM[.ss] format.
	     Parsing is	done using strptime(3).