edit shell_demo

1_3.test_code/sh_test/sh_demo.sh

@@ -0,0 +1,135 @@
+#!/bin/bash
+#以下代码中(())可替换为[]
+
+
+#--------------------------------------
+echo "var define"
+
+var="helo"          #定义变量不需加$
+echo ${var}         #使用变量时加$
+echo "---------------------------"
+echo ""
+
+#--------------------------------------
+echo "echo about str"
+
+#单引号中任何字符均原样输出
+#单引号里不能出现单引号（使用转义符也不行）
+single_str='helo'
+
+#双引号里可以有变量
+#双引号里可以出现转义字符
+double_str="hello,\" ${single_str} \" "
+echo $single_str
+echo $double_str
+echo "---------------------------"
+echo ""
+
+#--------------------------------------
+echo "字符串连接："
+#字符串连接
+#method 1
+echo "method1: ","helo", "helo"
+
+#method 2
+str="strcat"
+str2="helo"
+echo "method2:  ${str},${str2}"
+
+#method 3
+echo "method3:" ${str} ${str2}
+echo "---------------------------"
+echo ""
+
+#--------------------------------------
+echo "get strlen:"
+echo "strlen: ", "${#str}"
+echo "---------------------------"
+echo ""
+
+#--------------------------------------
+echo "substr:"
+substr="hello Meizu!"
+echo ${substr:1:4}
+echo "---------------------------"
+echo ""
+
+
+#--------------------------------------
+echo "查找子串: error"
+echo 'expr Meizu "${substr}"'
+echo "---------------------------"
+echo ""
+
+#--------------------------------------
+echo "for sh format:"
+
+for((i=0; i<10; i++)) do
+    echo $i
+done
+echo "---------------------------"
+echo ""
+
+#--------------------------------------
+echo "if-else:"
+min=10
+max=10
+if ((${min} < ${max})); then
+    echo "min < max"
+elif ((${min} > ${max})); then
+    echo "min > max"
+else
+    echo "min = max"
+fi
+echo "---------------------------"
+echo ""
+
+#--------------------------------------
+echo "while"
+var=10
+while ((${var} > 0)); do
+    var=$((var-1))
+    echo $var
+done
+echo "---------------------------"
+echo ""
+
+#--------------------------------------
+echo "执行shell命令，将结果赋给变量:"
+#var=`date`
+var=$(date)
+echo $var
+echo "---------------------------"
+echo ""
+
+#--------------------------------------
+echo "echo不换行:"
+# -e 开启转义 \c 不换行
+echo -e "OK! \c oo"    
+echo "---------------------------"
+echo ""
+
+#--------------------------------------
+echo -e "前台运行shell:\t\c"
+ls
+echo "后台运行shell："
+ls &
+echo "---------------------------"
+echo ""
+#--------------------------------------
+echo "/dev/null:"
+echo "helo" > /dev/null
+echo "---------------------------"
+echo ""
+
+#--------------------------------------
+echo '$?:'
+ls
+echo $?
+echo "---------------------------"
+echo ""
+
+#--------------------------------------
+echo HELLO'X'
+echo "---------------------------"
+echo ""

1_3.test_code/sh_test/test.sh

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