... abbreviations (Jan, Feb, Mar,Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec)5 Day of week 0–7 (0 and 7 both mean Sunday, 1 is Monday)Three letter day abbreviations (Sun, Mon, Tue,Wed, Thu, Fri, Sat)704 ... days since 1 January 1970 that the password was lastchanged710 Chapter 29THE SHADOW PASSWORD SYSTEM Red Hat Linux, like most, if not all, Linux and UNIX systems, uses shadowpasswords because ... Janu-ary, March, June, and September, the crontab entry would look like one of thefollowing:55 16 1,1 5 1,3 , 6,9 * incrback.sh55 16 1,1 5 Jan,Mar,Jun,Sep * incrback.shIn this case, the * in the day...