fish-shell/share/functions/__fish_complete_users.fish

function __fish_complete_users --description "Print a list of local users, with the real user name as a description"
    if test -x /usr/bin/getent
        getent passwd | cut -d : -f 1,5 | string replace -r ':' \t
    else if test -x /usr/bin/dscl
        dscl . -list /Users RealName | string match -r -v '^_' | string replace -r ' {2,}' \t
    else
        string match -v -r '^\s*#' </etc/passwd | cut -d : -f 1,5 | string replace ':' \t
    end
end