4BSD/usr/man/cat1/at.1

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AT(1)               UNIX Programmer's Manual                AT(1)



NAME
     at - execute commands at a later time

SYNOPSIS
     at time [ day ] [ file ]

DESCRIPTION
     _A_t squirrels away a copy of the named _f_i_l_e (standard input
     default) to be used as input to _s_h(1) (or _c_s_h(1) if you nor-
     mally use it) at a specified later time.  A _c_d command to
     the current directory is inserted at the beginning, followed
     by assignments to all environment variables (excepting the
     variable TERMCAP, which is useless in this context.) When
     the script is run, it uses the user and group ID of the
     creator of the copy file.

     The _t_i_m_e is 1 to 4 digits, with an optional following `A',
     `P', `N' or `M' for AM, PM, noon or midnight.  One and two
     digit numbers are taken to be hours, three and four digits
     to be hours and minutes.  If no letters follow the digits, a
     24 hour clock time is understood.

     The optional _d_a_y is either (1) a month name followed by a
     day number, or (2) a day of the week; if the word `week'
     follows invocation is moved seven days further off.  Names
     of months and days may be recognizably truncated.  Examples
     of legitimate commands are

          at 8am jan 24
          at 1530 fr week

     _A_t programs are executed by periodic execution of the com-
     mand /_u_s_r/_l_i_b/_a_t_r_u_n from _c_r_o_n(8).  The granularity of _a_t
     depends upon how often _a_t_r_u_n is executed.

     Standard output or error output is lost unless redirected.

FILES
     /usr/lib/atrun      executor (run by _c_r_o_n(8)).

     in /usr/spool/at:
          yy.ddd.hhhh.*  activity for year yy, day dd, hour hhhh.
          lasttimedone   last _h_h_h_h
          past           activities in progress

SEE ALSO
     calendar(1), pwd(1), sleep(1), cron(8)

DIAGNOSTICS
     Complains about various syntax errors and times out of
     range.




Printed 11/10/80                                                1






AT(1)               UNIX Programmer's Manual                AT(1)



BUGS
     Due to the granularity of the execution of /_u_s_r/_l_i_b/_a_t_r_u_n,
     there may be bugs in scheduling things almost exactly 24
     hours into the future.



















































Printed 11/10/80                                                2