If you want to print something as a pop-up on your screen or you can call it as GUI (graphical user interface) we have a lot of dialog boxes .
GTK is a graphical tool in Linux like qGUI .
To see manual we have 2 options
In zenity whatever you type should be stored somewhere.
zenity --entrynow ,lets store the data
this is a wrong way to store the data
Correct way :
(💡: No space before and after equal in shell scripting)
For more commands you can explore with the help of zenity manual .