终端结束之后，编译工具相关的环境变量都会失效。下次新开终端时，都要首先导出这些变量。
比如 $IDF_PATH 是指 esp-idf的路径。
Echo $IDF_PATH 检查一下这个路径是不是OK的
======增加快捷命令 .bash_profile
alias get_idf='. $HOME/xxxxxx/esp-idf/export.sh'
source ~/.bash_profile
导出环境变量:
get_idf
Echo $IDF_PATH检查一下
===== 开始 hello_world ====
复制hello_world代码
1.cp -r $IDF_PATH/examples/get-started/hello_world .
cd hello_world
idf.py set-target esp32c3 #环境变量导出OK，idf.py 就会有自动补齐功能
idf.py menuconfig #不做也可，默认115200波特率
idf.py build #编译工程
idf.py -p /dev/tty.wchusbserial1410 flash #烧录到板子上，自动刚开始运行 -b设置波特率 默认115200
idf.py -p /dev/tty.wchusbserial1410 monitor # 监听串口
ctrl+] 退出监听
Hello world!
This is esp32c3 chip with 1 CPU core(s), WiFi/BLE, silicon revision 3, 2MB external flash
Minimum free heap size: 329596 bytes
Restarting in 10 seconds...
Restarting in 9 seconds...
Restarting in 8 seconds...
Restarting in 7 seconds...
Restarting in 6 seconds...
Restarting in 5 seconds...
Restarting in 4 seconds...
Restarting in 3 seconds...
Restarting in 2 seconds...
Restarting in 1 seconds...
Restarting in 0 seconds...
Restarting now.
