1.\" 2.\" Sun Microsystems, Inc. gratefully acknowledges The Open Group for 3.\" permission to reproduce portions of its copyrighted documentation. 4.\" Original documentation from The Open Group can be obtained online at 5.\" http://www.opengroup.org/bookstore/. 6.\" 7.\" The Institute of Electrical and Electronics Engineers and The Open 8.\" Group, have given us permission to reprint portions of their 9.\" documentation. 10.\" 11.\" In the following statement, the phrase ``this text'' refers to portions 12.\" of the system documentation. 13.\" 14.\" Portions of this text are reprinted and reproduced in electronic form 15.\" in the SunOS Reference Manual, from IEEE Std 1003.1, 2004 Edition, 16.\" Standard for Information Technology -- Portable Operating System 17.\" Interface (POSIX), The Open Group Base Specifications Issue 6, 18.\" Copyright (C) 2001-2004 by the Institute of Electrical and Electronics 19.\" Engineers, Inc and The Open Group. In the event of any discrepancy 20.\" between these versions and the original IEEE and The Open Group 21.\" Standard, the original IEEE and The Open Group Standard is the referee 22.\" document. The original Standard can be obtained online at 23.\" http://www.opengroup.org/unix/online.html. 24.\" 25.\" This notice shall appear on any product containing this material. 26.\" 27.\" The contents of this file are subject to the terms of the 28.\" Common Development and Distribution License (the "License"). 29.\" You may not use this file except in compliance with the License. 30.\" 31.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 32.\" or http://www.opensolaris.org/os/licensing. 33.\" See the License for the specific language governing permissions 34.\" and limitations under the License. 35.\" 36.\" When distributing Covered Code, include this CDDL HEADER in each 37.\" file and include the License file at usr/src/OPENSOLARIS.LICENSE. 38.\" If applicable, add the following below this CDDL HEADER, with the 39.\" fields enclosed by brackets "[]" replaced with your own identifying 40.\" information: Portions Copyright [yyyy] [name of copyright owner] 41.\" 42.\" 43.\" Copyright 1989 AT&T 44.\" Portions Copyright (c) 1992, X/Open Company Limited All Rights Reserved 45.\" Portions Copyright (c) 1982-2007 AT&T Knowledge Ventures 46.\" Copyright (c) 2007, Sun Microsystems, Inc. All Rights Reserved Portions 47.\" Copyright 2019 Robert Mustacchi 48.\" 49.Dd September 12, 2019 50.Dt SLEEP 1 51.Os 52.Sh NAME 53.Nm sleep 54.Nd suspend execution for an interval 55.Sh SYNOPSIS 56.Nm sleep 57.Ar time[suffix] 58.Sh DESCRIPTION 59.Nm 60suspends execution for at least the time in seconds specified by 61.Ar time 62or until a 63.Dv SIGALRM 64signal is received. 65The 66.Ar time 67operand can be specified as a non-negative floating point number but the 68actual granularity depends on the underlying system. 69The 70.Ar time 71operand may be passed as a decimal or hexadecimal string. 72Other floating point values such as Inf or infinity are also honored. 73.Pp 74A single suffix may be applied to the 75.Ar time 76operand to represent units other than seconds. 77Supported suffixes for the 78.Ar suffix 79operand include: 80.Bl -tag -offset indent -width 6n 81.It Sy s 82Represents time in seconds. 83.It Sy m 84Represents time in minutes. 85.It Sy h 86Represents time in hours. 87.It Sy d 88Represents time in days. 89.It Sy w 90Represents time in weeks. 91.It Sy y 92Represents time in years. 93.El 94.Pp 95The use of suffixes is generally not portable to other systems. 96.Ss Signals 97If the 98.Nm 99program receives a signal, unless it is the 100.Dv SIGALRM 101signal, it will follow with the default signal handling disposition. 102If such a signal would interrupt the sleep, then the program may 103terminate with an error. 104.Sh EXIT STATUS 105The following exit values are returned: 106.Bl -inset 107.It Sy 0 108The execution was successfully suspended for at least 109.Ar time 110seconds, or a 111.Dv SIGALRM 112signal was received. 113.It Sy >0 114An error has occurred. 115.El 116.Sh EXAMPLES 117.Sy Example 1 118Suspending Command Execution 119.Pp 120The following example executes a command after a certain amount of time: 121.Bd -literal -offset indent 122example% \fB(sleep 105; \fIcommand\fR)&\fR 123.Ed 124.Pp 125.Sy Example 2 126Executing a Command Every So Often 127.Pp 128The following example executes a command every so often: 129.Bd -literal -offset indent 130example% \fBwhile true; do 131 \fIcommand\fR 132 sleep 37 133done\fR 134.Ed 135.Pp 136.Sy Example 3 137Suspend command execution forever 138.Po 139or until a 140.Dv SIGALRM 141signal is received 142.Pc 143.Bd -literal 144example% sleep Inf 145.Ed 146.Pp 147.Sy Example 4 148Suspending command execution for 0.5 seconds 149.Pp 150Suspending command execution for 0.5 seconds using an alternative 151floating-point representation for the value "0.5". 152.Bd -literal 153example% printf "%a\en" 0.5 1540x1.0000000000000000000000000000p-01 155example% sleep 0x1.0000000000000000000000000000p-01 156.Ed 157.Sh ENVIRONMENT VARIABLES 158See 159.Xr environ 7 160for descriptions of the following environment variables 161that affect the execution of 162.Nm : 163.Ev LANG , 164.Ev LC_ALL , 165.Ev LC_MESSAGES , 166.Ev LC_NUMERIC , 167and 168.Ev NLSPATH . 169.Sh INTERFACE STABILITY 170.Sy Committed 171.Sh SEE ALSO 172.Xr wait 1 , 173.Xr alarm 2 , 174.Xr nanosleep 3C , 175.Xr sleep 3C , 176.Xr environ 7 177