Aqui está uma versão com mas tenho a certeza que existe uma forma mais compacta de o fazer
#!/bin/bash
WORD=$@
NUMBER_OF_SPACES_SURROUNDING_THE_WORD=1
TERMINAL_WIDTH=$(tput cols)
WORD_SIZE=$(echo $WORD | wc -c )
NUMBER_OF_SPACES_SURROUNDING_THE_WORD=1
NUMBER_OF_SYMBOLS=$((TERMINAL_WIDTH - $WORD_SIZE - 2*$NUMBER_OF_SPACES_SURROUNDING_THE_WORD))
LENGTH_OF_RIGHT_PART=$((NUMBER_OF_SYMBOLS/2 + $NUMBER_OF_SYMBOLS%2 ))
LENGTH_OF_LEFT_PART=$(( $TERMINAL_WIDTH - 2*$NUMBER_OF_SPACES_SURROUNDING_THE_WORD - $WORD_SIZE - $LENGTH_OF_RIGHT_PART ))
printf '%*s' "$LENGTH_OF_RIGHT_PART" '' | tr " " -
printf '%*s' $NUMBER_OF_SPACES_SURROUNDING_THE_WORD
printf $WORD
printf '%*s' $NUMBER_OF_SPACES_SURROUNDING_THE_WORD
printf '%*s\n' "$LENGTH_OF_RIGHT_PART" '' | tr " " -