UNIX for Beginners Questions & Answers

#!/bin/bash
ext=new$$
for arg
do
  set 01 02 03
  changed=
  while IFS= read line
  do
    case $line in
    (*tcname*)
      echo "${line//tcname/$1}"
      shift
      changed=1
    ;;
    (*)
      echo "$line"
    ;;
    esac
  done <"$arg" >"$arg.$ext" &&
  [ -n "$changed" ] &&
  cp "$arg.$ext" "$arg"
  rm "$arg.$ext"
done

replace.sh file1

rm "$arg.$ext"

cat "$arg.$ext"
rm $_