I want to run firefox as two instances or applications, with each running a different website with two different application icons. I tried firefox -no-remote but it returns an error as a pop-up :
Does anyone know how to get over with this? I tried this question, but did not work out.
You can create a new desktop shortcut, eg. new .desktop file. So let say that you have:
firefox2.desktop
[Desktop Entry]
.....
Exec= firefox -no-remote -P ProfileName
Icon=path/to/your/special/icon/or/com/location/
Also if you drop ProfileName you would get menu for creating new profile, or selecting old one.
Next step will be configuring taskbar, for example if you are using KDE Plasma, you can configure taskbar/icon-only taskbar to group of ungroup icons. For exact instructions you need to provide exact name of your DE and taskbar you are using(built-in , extension etc.) So icon on the desktop would be different, but taskbar icon will be the same(default or icon-theme based) but ungrouped.
For better answer(and if this is not your desired result), please provide which DE and taskbar are you using.
P.S. You got that error because you opened new Firefox instance with the same profile.
EDIT:
GNOME 3.18 - 3.38
You can use extension called Dash to Panel, it is very easy to configure it via Gnome Tweaks (you can install it via sudo apt install gnome-shell-extensions).
KDE PLASMA
For task manager you are probably using task manager extension or icon-only task manager, both of them con be configured via righ-click -> Configure -> Behaviour-> group.
Worked on Ubuntu 22.04
The only way I managed to make 2 independently firefox shortcuts in the dock (one of them with different icon), where its windows are gathered with its corresponding icon, was to install a deb firefox along with the snap firefox.
##########################
#Disable snap firefox
sudo snap disable firefox
sudo apt remove --autoremove firefox -y
##########################
#Install .deb firefox
sudo add-apt-repository ppa:mozillateam/ppa -y
sudo apt-get update -y
sudo apt-get upgrade -y
#Set firefox updates priority for the .deb repository
sudo bash -c 'cat > /etc/apt/preferences.d/99mozillateamppa <<EOF
Package: firefox*
Pin: release o=LP-PPA-mozillateam
Pin-Priority: 501
Package: firefox*
Pin: release o=Ubuntu
Pin-Priority: -1
EOF'
sudo apt install -t 'o=LP-PPA-mozillateam' firefox -y
#the deb is installed in /usr/lib/firefox
###########################
enable snap firefox again
sudo snap enable firefox
#########################
change firefox icon
old="Icon=firefox"
new="Icon=/path/to/your/icon"
sudo sed -i "/${old}/c ${new}" /usr/share/applications/firefox.desktop
#change .deb firefox name
old="Name=Firefox Web Browser"
new="Name=FirefoxSecond"
sudo sed -i "/${old}/c ${new}" /usr/share/applications/firefox.desktop
To open firefoxSecond (.deb) :
firefox
To open firefox( snap) :
snap run firefox
Now add them to favorites!
