for example

find . -iname "*.qmltypes" -exec sed -i 's/.*DLT.*WARNING.*/ /' {} +

or git clean -d -f- x

or something like make -C ../build/ generate_assets

I would like to have possibility to execute user defined command by pressing a button or a menu item

I mean execution of a command itself, not a showing me a terminal window. Like a calling external tools in qt creator.