.TH AT 1 .SH NAMEat \- execute commands at a later time.SH SYNOPSIS.B attime[day][file].SH DESCRIPTION.I Atsquirrels away a copy of the named.I file(standard input default)to be used as input to.IR sh (1)at a specified later time.A.IR cd (1)command to the current directory is insertedat the beginning,followed by assignments to all environment variables.When the script is run, it uses the user and group IDof the creator of the copy file..PPThe.I timeis 1 to 4 digits, with an optional following`A', `P', `N' or `M' forAM, PM, noon or midnight.One and two digit numbers are taken to be hours, three and four digitsto be hours and minutes.If no letters follow the digits, a 24 hour clock time is understood..PPThe optional.I dayis either(1) a month name followed by a day number,or(2) a day of the week; if the word `week' followsinvocation is moved seven days further off.Names of months and days may be recognizably truncated.Examples of legitimate commands are.IPat 8am jan 24.brat 1530 fr week.PP.I Atprograms are executed by periodic executionof the command.I /usr/lib/atrunfrom.IR cron (8).The granularity of.I atdepends upon how often.I atrunis executed..PPStandard output or error output is lost unless redirected..SH FILES/usr/spool/at/yy.ddd.hhhh.uu.bractivity to be performed at hour.I hhhhof year day.I dddof year.IR yy ..I uuis a unique number..br/usr/spool/at/lasttimedone contains.I hhhhfor last hour of activity..br/usr/spool/at/past directory of activities now in progress.br/usr/lib/atrun program that executes activities thatare due.brpwd(1).SH "SEE ALSO"calendar(1),cron(8).SH DIAGNOSTICSComplains about various syntax errors and times out of range..SH BUGSDue to the granularity of the execution of.I /usr/lib/atrun,there may be bugs in scheduling things almostexactly 24 hours into the future.