Fish uses options on the set
command to manipulate shell variables.
Unset a variable with the -e
or --erase
option.
set -e myvar
Additionally you can define a function
function unset
set --erase $argv
end
funcsave unset
or an abbreviation
abbr --add unset 'set --erase'
or an alias in ~/.config/fish/config.fish
alias unset 'set --erase'