test sh run in background

1_3.test_code/sh_test/background_exec.sh

@@ -0,0 +1,15 @@
+#!/bin/bash
+function fileNum(){
+while true
+do
+    echo "sleep background"
+    sleep 5
+done
+}
+fileNum &
+while true
+do
+    echo "sleep foreground"
+    sleep 1
+done
+

1_3.test_code/sh_test/fork_shell.sh

@@ -0,0 +1,3 @@
+#!/bin/bash
+sh -c "exec ./test.sh"
+echo abc

1_3.test_code/sh_test/random.sh

@@ -0,0 +1,14 @@
+#!/bin/sh
+random_num=$(date +%s%N)
+echo $random_num
+
+#指定范围随机数
+rand(){  
+    min=$1  
+    max=$(($2-$min+1))  
+    num=$(date +%s%N)  
+    echo $(($num%$max+$min))  
+}  
+random_num2=$(rand 1 3)
+sleep ${random_num2}
+echo $random_num2

1_3.test_code/sh_test/test.sh

@@ -0,0 +1,3 @@
+#!/bin/bash 
+ps
+echo "hello world"