NAME
sat - A simple incompatible implementation of at(1).
DESCRIPTION
sat is a simple implementation of at(1). But is not compatible
with at(1). It is used to queue jobs to be executed later, outside
the current controlling terminal.
sat can also print and edit the list of queued jobs.
If you are using autohaltd(8), you should set up hooks for at(1)
that pauses autohaltd(8) using SIGSTOP (and resume with SIGCONT)
when there are queued jobs. This would prevent autohaltd(8) from
shuting down the machine while there are queued jobs but no logins.
sat cannot stop autohaltd(8) by adding login entries, because
autohaltd(8) will only recognise them if they are in fact true
logins.
RATIONALE
at(1) is far too complex.
sat does not do natural language time parsing, it is far too complex,
and locale dependent, for all programs to implemeent and should be
done in a separate program. Not even GNU date(1) gets this right.
sat does however do some trivial parsing.
sat does not sanitise the environment. You have env(1) for that.
Relaying on sat to sanitise the environment appropriately could prove
to be a misfortune.
sat does not do mailing because that is very restrictive, hooks are
used instead.
sat does not do system load analysis, this should be done in a
separate program.
sat only has one queue, queue can easily be emulated using dummy
commands, for example instead of 'my command', you can run
'sh -c ": QUEUE-a ; my command"'.
at(1) should not be merged into cron(8). cron(8) does recurring
scheduled jobs, at(1) does one-time unscheduled jobs. atq(1) does
not translate to cron(8).
ENVIRONMENT
XDG_RUNTIME_DIR
This environment variable names the directory in which
interprocess communication related files are stored. If
unset or empty, /run is used.
SAT_HOOK_PATH
The pathname of the hook script to use. Does not have to
already exist. If not defined, $XDG_CONFIG_HOME/sat/hook
(if XDG_CONFIG_HOME is defined), $HOME/.config/sat/hook
(if HOME is defined), ~/.config/sat/hook (if the user has
a home and is not root), or /etc/sat/hook (otherwise) is
used.
FUTURE DIRECTIONS
sat-atcompat will be written to bring compatibility with
old school at(1).
NOTES
nohup(1) combined with sh(1) and, sleep(1) or sleep-until(1)
should be sufficient for most users.
SEE ALSO
at(1), cron(1), sleep-until(1)
