32v 1m at
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AT(1) UNIX Programmer's Manual AT(1)
at - execute commands at a later time
at time [ day ] [ file ]
_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) at a specified later time. A _c_d(1) command to the current directory is inserted at the beginning, followed by assignments to all environment variables. 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(1). 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.
/usr/spool/at/yy.ddd.hhhh.uu activity to be performed at hour _h_h_h_h of year day _d_d_d of year _y_y. _u_u is a unique number. /usr/spool/at/lasttimedone contains _h_h_h_h for last hour of activity. /usr/spool/at/past directory of activities now in progress /usr/lib/atrun program that executes activities that are due pwd(1)
Complains about various syntax errors and times out of range.
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.