# Shell learning *system service* ###### tags: `shell` Copyright 2021, [月下麒麟 YMont](https://hackmd.io/@YMont/note-catalog) --- ## outline 學習shell腳本與linux指令認識 ## command ```which python3``` ![](https://i.imgur.com/EBsye2n.png) ```which python3 | sed 's/\//\\\//g'``` ![](https://i.imgur.com/S2q4LOs.png) 產生反斜線(backslash) ```cat main.py | sed "s/python/java/g" > `pwd`/main``` ![](https://i.imgur.com/8SMciQi.png) main(.py) ![](https://i.imgur.com/479xhou.png) main(no file extension) ``` cat `pwd`/main```(補充) ![](https://i.imgur.com/l8q8QjO.png) ```ln -sf /test.service /etc/systemd/system/``` ![](https://i.imgur.com/ifC3Ww0.png) 建立軟連結至系統配置處(administrate) ![](https://i.imgur.com/ulH5CSx.png) 於/etc/systemd/system就會看到該main.service被連結在此 ```sudo systemctl enable main``` 即可針對該service執行啟用 systemctl 的 start 與 stop 兩個操作指令是用來控制目前服務的狀態 如果想要設定開機自動啟動服務的話，就要改用 enable 與 disable Reference:[Linux 指令 SED 用法教學、取代範例、詳解](https://terryl.in/zh/linux-sed-command/) Reference:[Linux systemd 系統服務管理基礎教學與範例](https://blog.gtwang.org/linux/linux-basic-systemctl-systemd-service-unit-tutorial-examples/)