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37 .Nd suspend execution for an interval of time
40 .Ar number Ns Op Ar unit
45 command suspends execution for a minimum of
47 seconds (the default, or unit
55 If multiple arguments are passed, the delay will be the sum of all values.
59 command receives a signal, it takes the standard action.
62 signal is received, the estimate of the amount of seconds left to
63 sleep is printed on the standard output.
64 .Sh IMPLEMENTATION NOTES
67 signal is not handled specially by this implementation.
71 command supports other time units than seconds,
72 honors a non-integer number of time units to sleep in any form acceptable by
74 and accepts more than one delay value.
75 These are non-portable extensions, but they have also been implemented
76 in GNU sh-utils since version 2.0a (released in 2002).
80 To schedule the execution of a command for
82 number seconds later (with
85 .Dl (sleep 1800; sh command_file >& errors)&
87 This incantation would wait a half hour before
88 running the script command_file.
93 To reiteratively run a command (with the
96 .Bd -literal -offset indent -compact
98 if (! -r zzz.rawdata) then
101 foreach i (`ls *.rawdata`)
103 awk -f collapse_data $i >> results
110 The scenario for a script such as this might be: a program currently
111 running is taking longer than expected to process a series of
112 files, and it would be nice to have
113 another program start processing the files created by the first
114 program as soon as it is finished (when zzz.rawdata is created).
115 The script checks every five minutes for the file zzz.rawdata,
116 when the file is found, then another portion processing
117 is done courteously by sleeping for 70 seconds in between each
125 command is expected to be