Description of Use
The Usleep command is used to delay the time in microseconds (sleep some number of microseconds), which actually does not reach this precision (Probably not accurate on many machines the mic Rosecond. Count on precision only to-4 or maybe-5.). If there is no usleep command in the system, you can use the Sleep command, and the Sleep command can specify a time delay with a decimal. 1 seconds =1000 milliseconds =1000,000 microseconds =1000,000,000 nanoseconds. Common Ways
Format: Usleep <us>
Latency <us> microseconds.
using the example Example one usleep command accuracy test
[Root@jfht ~]# date +%s.%n; Usleep Date +%s.%n
04.194798315
04.199352948
[Root@jfht ~]# date +%s.%n; Usleep Date +%s.%n
12.684509970
12.688986355
[Root@jfht ~]# date +%s.%n; Usleep 1000; Date +%s.%n
33.179766926
33.186719087
[Root@jfht ~]# date +%s.%n; Usleep 10000; Date +%s.%n
45.556317402
45.571467950
[Root@jfht ~]# date +%s.%n; Usleep 100000; Date +%s.%n
59.656176597
59.761001631
[Root@jfht ~]# date +%s.%n; Usleep 1000000; Date +%s.%n
56.700405298
57.704304279
[Root@jfht ~]#
Example two sleep command accuracy test
[Root@jfht ~]# date +%s.%n; Sleep 1; Date +%s.%n
47.111204217
48.115898894
[Root@jfht ~]# date +%s.%n; Sleep 0.1; Date +%s.%n
57.760602228
57.865456080
[Root@jfht ~]# date +%s.%n; Sleep 0.01; Date +%s.%n
08.912279911
08.927840798
[Root@jfht ~]# date +%s.%n; Sleep 0.001; Date +%s.%n
18.171663617
18.176771668
[Root@jfht ~]# date +%s.%n; Sleep 0.0001; Date +%s.%n
27.290651737
27.295785240
[Root@jfht ~]#
Problem Thinking Related Information
"1" nixway.net usleep (1) Command reference
http://www.nixway.net/index.php?manitem&mid=2558
"2" linuxsir.org Ubuntu usleep command is not available, which package to pack it.
http://www.linuxsir.org/bbs/showthread.php?t=315109
http://codingstandards.iteye.com/blog/1007783