https://bencane.com/2014/06/06/8-tips-for-creating-better-bash-scripts/

====== remove old files ======

find /path/to/files* -mtime +5 -exec rm {} \;

====== Headline ======

[[https://devhints.io/bash|Bash scripting cheatsheet]]


[[https://www.jasonmayberry.net/2019/06/new-bash-linux-cheatsheet-wallpaper.html|new bash Linux Cheatsheet Wallpaper]]

====== sed / awk / opkg  ======

  * find packages installed asterisk15 and prepare the cmd for asterisk16 installation

  opkg list_installed | grep asterisk | awk '{print $1}' | sed 's/^/opkg install /' | sed 's/asterisk15/asterisk16/'