Fish provides a set of commands for configuring your shell directly in the terminal, eliminating the need to edit a config file. In zsh and bash, you would typically open ~/.bashrc or ~/.zshrc to add your own config. Similarly, in Fish, you can edit /.config/fish/config.fish. However, Fish offers convenient commands to fulfill most of your configuration needs. To begin with, start typing fish_ in terminal and press TAB. You’ll see a list of commands. Some of my favorites are:

fish_greeting

This is the message Fish displays the first time you open a terminal tab. Use the set -g command to change it to whatever you want. -g stands for global variable (see MAN page for set).

set -g fish_greeting 'Oh shit, here we go again...'

The result:

fish_config

Opens a config page like this in your browser:

On top of customizing your Fish theme, you can also change the default prompt you see in Fish, see a list of available functions (including the ones you have defined in config.fish), see all (environmental) variables, view history (it’s quite long…), and see all keyboard shortcuts (bindings) supported by Fish.