如何获得后台进程的PID？

Question

我从我的shell脚本开始后台进程,我想在脚本完成时终止这个进程.

如何从我的shell脚本中获取此进程的PID？据我所知,变量$!包含当前脚本的PID,而不是后台进程.

Answer 1

您需要在启动时保存后台进程的PID:

foo &
FOO_PID=$!
# do other stuff
kill $FOO_PID

您无法使用作业控制,因为这是一个交互式功能并且与控制终端绑定.脚本根本不需要连接终端,因此不一定可以使用作业控制.

Answer 2

您可以使用该jobs -l命令访问特定的jobL

^Z
[1]+  Stopped                 guard

my_mac:workspace r$ jobs -l
[1]+ 46841 Suspended: 18           guard

在这种情况下,46841是PID.

来自help jobs:

-l报告作业的进程组ID和工作目录.

jobs -p 是另一个显示PID的选项.

Answer 3

• $$ 是当前脚本的pid
• $! 是最后一个后台进程的pid

这是来自bash会话的示例脚本(%1指从后面看到的后台进程的序号jobs):

$ echo $$
3748

$ sleep 100 &
[1] 192

$ echo $!
192

$ kill %1

[1]+  Terminated              sleep 100

Answer 4

杀死bash脚本的所有子进程的更简单方法:

pkill -P $$

该-P标志与pkilland的工作方式相同pgrep- 它获取子进程,只有pkill子进程被杀死并且pgrep子PID被打印到stdout.

Answer 5

这就是我所做的。看看吧，希望能帮到你。

#!/bin/bash
#
# So something to show.
echo "UNO" >  UNO.txt
echo "DOS" >  DOS.txt
#
# Initialize Pid List
dPidLst=""
#
# Generate background processes
tail -f UNO.txt&
dPidLst="$dPidLst $!"
tail -f DOS.txt&
dPidLst="$dPidLst $!"
#
# Report process IDs
echo PID=$$
echo dPidLst=$dPidLst
#
# Show process on current shell
ps -f
#
# Start killing background processes from list
for dPid in $dPidLst
do
        echo killing $dPid. Process is still there.
        ps | grep $dPid
        kill $dPid
        ps | grep $dPid
        echo Just ran "'"ps"'" command, $dPid must not show again.
done

然后只需将其运行为：./bgkill.sh当然具有适当的权限

root@umsstd22 [P]:~# ./bgkill.sh
PID=23757
dPidLst= 23758 23759
UNO
DOS
UID        PID  PPID  C STIME TTY          TIME CMD
root      3937  3935  0 11:07 pts/5    00:00:00 -bash
root     23757  3937  0 11:55 pts/5    00:00:00 /bin/bash ./bgkill.sh
root     23758 23757  0 11:55 pts/5    00:00:00 tail -f UNO.txt
root     23759 23757  0 11:55 pts/5    00:00:00 tail -f DOS.txt
root     23760 23757  0 11:55 pts/5    00:00:00 ps -f
killing 23758. Process is still there.
23758 pts/5    00:00:00 tail
./bgkill.sh: line 24: 23758 Terminated              tail -f UNO.txt
Just ran 'ps' command, 23758 must not show again.
killing 23759. Process is still there.
23759 pts/5    00:00:00 tail
./bgkill.sh: line 24: 23759 Terminated              tail -f DOS.txt
Just ran 'ps' command, 23759 must not show again.
root@umsstd22 [P]:~# ps -f
UID        PID  PPID  C STIME TTY          TIME CMD
root      3937  3935  0 11:07 pts/5    00:00:00 -bash
root     24200  3937  0 11:56 pts/5    00:00:00 ps -f