问题
What is difference between wait and sleep?
回答1:
wait waits for a process to finish; sleep sleeps for a certain amount of seconds.
回答2:
wait is a BASH built-in command. From man bash:
wait [n ...]
Wait for each specified process and return its termination sta-
tus. Each n may be a process ID or a job specification; if a
job spec is given, all processes in that job's pipeline are
waited for. If n is not given, all currently active child pro-
cesses are waited for, and the return status is zero. If n
specifies a non-existent process or job, the return status is
127. Otherwise, the return status is the exit status of the
last process or job waited for.
sleep is not a shell built-in command. It is a utility that delays for a specified amount of time.
The sleep command may support waiting in various units of time. GNU coreutils 8.4 man sleep says:
SYNOPSIS
sleep NUMBER[SUFFIX]...
DESCRIPTION
Pause for NUMBER seconds. SUFFIX may be ‘s’ for seconds (the default),
‘m’ for minutes, ‘h’ for hours or ‘d’ for days. Unlike most implemen-
tations that require NUMBER be an integer, here NUMBER may be an arbi-
trary floating point number. Given two or more arguments, pause for
the amount of time specified by the sum of their values.
回答3:
sleep just delays the shell for the given amount of seconds.
wait makes the shell wait for the given job. e.g.:
workhard &
[1] 27408
workharder &
[2] 27409
wait %1 %2
delays the shell until both of the subprocesses have finished
回答4:
Bash
wait command stop script execution until all jobs running in background have terminated or until the job number or process id specified as an option terminates
wait%1 or wait $PID
wait ${!}
wait ${!} means "to wait till the last background process is completed" ($! being the PID of the last background process)
Sleep
add delay for a specified amount of time.
sleep NUMBER[SUFFIX]
sleep 5 (sleep five seconds)
回答5:
Try this:
sleep 10 &
wait %1
来源：https://stackoverflow.com/questions/13296863/difference-between-wait-and-sleep