Bash script to display progress (to stderr) by counting lines from stdin.

progress.sh

#!/bin/bash
  
#
# Displays progress (to stderr) by counting lines from stdin.
#
# Usage: <command> | progress.sh <expected-line-count> > <file>
#

total=$(( ${1:-0} ))
number=0
while read line; do
  number=$(( number+1 ))
  if [ $total -gt 0 ]; then
    percent=$(( number*100/total ))
    >&2 echo -en "  $percent%\r"
  fi
  echo $line
done