Screen adaptive head(1) and tail(1) functions.

Bash:

function hed {
    head -n $(( $(tput lines) - $(eval "wc -l <<<$'$PS1'") )) "$@"
}

function tal {
    tail -n $(( $(tput lines) - $(eval "wc -l <<<$'$PS1'") )) "$@"
}

Zsh:

function hed {
    head -n $(( $(tput lines) - $(wc -l <<<"$PS1") )) $@
}

function tal {
    tail -n $(( $(tput lines) - $(wc -l <<<"$PS1") )) $@
}

Note that my Zsh PS1 has real newlines in it, so there is no need for eval.

Inspiration.