To run VHDL programs in Ubuntu, follow these steps & type the commands in terminal.
sudo apt update
sudo apt install ghdl -y
sudo apt install gtkwave -y
You can check if ghdl and gtkwave have been installed or not by typing the following commands,
ghdl --version
gtkwave --version
If their versions show up they have been installed; otherwise there may have been some problems during installation.
Use commands like ls and cd to navigate to the directory containing the VHDL program.
make
gtkwave result.vcd
Now, gtkwave will open, allowing you to visualize the results (waveform) of your VHDL program.
You can zoom in & zoom out the waveform by clicking '+' & '-' respectively.