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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 Intervals can be written in any form allowed by
57 If multiple intervals are given, they are added together.
58 If the final sum is zero or negative,
64 command receives a signal, it takes the standard action.
67 signal is received, the estimate of the amount of seconds left to
68 sleep is printed on the standard output.
69 .Sh IMPLEMENTATION NOTES
72 signal is not handled specially by this implementation.
76 To run a command after half an hour:
78 .Dl (sleep 0.5h; sh command_file >out 2>err)&
80 This incantation would wait half an hour before
85 utility for another way to do this.
87 To reiteratively run a command:
89 .Bd -literal -offset indent -compact
91 if ! [ -r zzz.rawdata ] ; then
94 for i in *.rawdata ; do
96 awk -f collapse_data "$i"
103 The scenario for a script such as this might be: a program currently
104 running is taking longer than expected to process a series of
105 files, and it would be nice to have
106 another program start processing the files created by the first
107 program as soon as it is finished (when
110 The script checks every five minutes for the file
112 when the file is found, then another portion processing
113 is done courteously by sleeping for 70 seconds in between each
122 command is expected to be
126 Support for non-integer intervals, units other than seconds, and
127 multiple intervals which are added together are non-portable
128 extensions first introduced in GNU sh-utils 2.0a (released in 2002).