The count command does not accept any options, not even '-h'. This way the user does not have to worry about an array containing elements such as dashes. fish performs a special check when invoking the count program, and if the user uses a help option, this help page is displayed, but if a help option is contained inside of a variable or is the result of expansion, it will be passed on to the count program.
Count exits with a non-zero exit status if no arguments where passed to it, with zero otherwise.
count $PATH
returns the number of directories in the users PATH variable.
count *.txt
returns the number of files in the current working directory ending with the suffix '.txt'.