#Bash 的 bg 命令

wait [OPTION]... [ID]...

功能

等待作业完成并返回退出状态。

类型

Bash 内置命令。

参数

OPTION 选项：
- -n - 等待 ID 列表中的单个作业；而非全部作业
- -p VAR - 将返回值赋值给变量 VAR
- -f - 等待作业结束；而非状态改变
ID - 进程 ID，可以使用以下特殊参数
- %1 - 第一个作业的进程 ID，以此类推
- %+ - 当前作业（最后一个暂停的作业）的进程 ID
- %- - 上一个作业（最后一个后台作业）的进程 ID

#示例

$ wait %1 %2
[1]-  Done                    sleep 10
[2]+  Done                    sleep 20

#推荐阅读

Job Control Builtins

#手册

wait: wait [-fn] [-p var] [id ...]
    Wait for job completion and return exit status.

    Waits for each process identified by an ID, which may be a process ID or a
    job specification, and reports its termination status.  If ID is not
    given, waits for all currently active child processes, and the return
    status is zero.  If ID is a job specification, waits for all processes
    in that job's pipeline.

    If the -n option is supplied, waits for a single job from the list of IDs,
    or, if no IDs are supplied, for the next job to complete and returns its
    exit status.

    If the -p option is supplied, the process or job identifier of the job
    for which the exit status is returned is assigned to the variable VAR
    named by the option argument. The variable will be unset initially, before
    any assignment. This is useful only when the -n option is supplied.

    If the -f option is supplied, and job control is enabled, waits for the
    specified ID to terminate, instead of waiting for it to change status.

    Exit Status:
    Returns the status of the last ID; fails if ID is invalid or an invalid
    option is given, or if -n is supplied and the shell has no unwaited-for
    children.

#Bash 的 bg 命令

#示例

#推荐阅读

#手册

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