#!/usr/bin/env bash
CHAR='.'; NCHAR=$2; LENGTH=4
fill_line(){
L=''
let TOT=$LENGTH-$1-1; let TOT*=2; let TOT+=1
I=0; while [[ $I -lt $1 ]]; do L="$L "; let I+=1; done
I=0; while [[ $I -lt $TOT ]]; do L="$L$CHAR"; let I+=1; done
echo "$L"
}
if [[ "x$1" == "x-h" || "x$1" == "x--help" ]]; then echo -e "Usage: `basename $0` [<size>] [<character>]\n"; exit; fi
if [[ "x$1" != "x" ]]; then LENGTH=$1; fi
if [[ "$NCHAR" != '' && "$NCHAR" != ' ' ]]; then CHAR=$NCHAR; fi
if [[ $LENGTH -le 1 ]]; then echo "$CHAR"; exit; fi
LINE=1; OPER="+1"
while [[ $LINE -ne 0 ]]
do
let SPACES=$LENGTH-$LINE
fill_line $SPACES
let LINE=$LINE$OPER
if [[ $LINE -ge $LENGTH ]]; then OPER="-1"; fi
done