shell脚本多进程

shell脚本再执行过程中就一个进程，从头到尾

下面配置shell脚本执行过程中启动多个进程同时执行

#!/bin/bash

for ((i=1;i<=10;i++))
do
(
  echo "$i"
  sleep 10
) &
done
wait
echo -E "########## $SECONDS ##########"

注：

$SECONDS：是执行完脚本所用的时间

wait：是等待所有的进程执行完毕

执行结果

[root@wcy ~]# bash test.sh
1
2
3
4
5
6
7
8
9
10
########## 10 ##########

进程查看

[root@wcy ~]# ps -ef | grep test.sh
root 1764 1565 0 19:23 pts/1 00:00:00 bash test.sh
root 1765 1764 0 19:23 pts/1 00:00:00 bash test.sh
root 1766 1764 0 19:23 pts/1 00:00:00 bash test.sh
root 1767 1764 0 19:23 pts/1 00:00:00 bash test.sh
root 1770 1764 0 19:23 pts/1 00:00:00 bash test.sh
root 1772 1764 0 19:23 pts/1 00:00:00 bash test.sh
root 1773 1764 0 19:23 pts/1 00:00:00 bash test.sh
root 1774 1764 0 19:23 pts/1 00:00:00 bash test.sh
root 1776 1764 0 19:23 pts/1 00:00:00 bash test.sh
root 1777 1764 0 19:23 pts/1 00:00:00 bash test.sh
root 1778 1764 0 19:23 pts/1 00:00:00 bash test.sh
root 1786 1708 0 19:23 pts/2 00:00:00 grep test.sh

[root@wcy ~]# ps -ef | grep test.sh | grep -v grep | wc -l
11

查看同一时刻多少个sleep在跑

[root@wcy ~]# ps -ef | grep sleep | grep -v grep
root 2168 2165 0 21:59 pts/1 00:00:00 sleep 10
root 2169 2166 0 21:59 pts/1 00:00:00 sleep 10
root 2172 2167 0 21:59 pts/1 00:00:00 sleep 10
root 2174 2171 0 21:59 pts/1 00:00:00 sleep 10
root 2175 2173 0 21:59 pts/1 00:00:00 sleep 10
root 2176 2170 0 21:59 pts/1 00:00:00 sleep 10
root 2179 2177 0 21:59 pts/1 00:00:00 sleep 10
root 2181 2178 0 21:59 pts/1 00:00:00 sleep 10
root 2182 2180 0 21:59 pts/1 00:00:00 sleep 10
root 2184 2183 0 21:59 pts/1 00:00:00 sleep 10

　　

[root@wcy ~]# ps -ef | grep sleep | grep -v grep  | wc -l
10

多进程的shell脚本可以用于并行执行多任务

#!/bin/bash
for ((i=1;i<=1;i++))
do
(
for ((num=1;num<=100;num++))
do
  echo "task1-- $num"
  sleep 1
done
) &
(
for ((ber=1;ber<=100;ber++))
do
  echo "task2-- $ber"
  sleep 1
done
) &
done
wait

效果，两个同时执行

[root@wcy ~]# bash duo.sh
task2-- 1
task1-- 1
task2-- 2
task1-- 2
task2-- 3
task1-- 3
task2-- 4
task1-- 4
········

脚本进程

[root@wcy ~]# ps -ef | grep duo.sh | grep -v grep
root 2221 1491 0 22:13 pts/0 00:00:00 bash duo.sh
root 2222 2221 0 22:13 pts/0 00:00:00 bash duo.sh
root 2223 2221 0 22:13 pts/0 00:00:00 bash duo.sh

同时执行的进程

[root@wcy ~]# ps -ef | grep sleep | grep -v grep
root 2357 2223 0 22:14 pts/0 00:00:00 sleep 1
root 2358 2222 0 22:14 pts/0 00:00:00 sleep 1