extension_checker

#!/bin/bash

IFS=$'\n'

for file in `realpath -- $@`; do
  [ -f $file ] || continue

  case `file -bi $file` in
    video/x-msvideo) EXT="avi" ;;
    video/mpeg) EXT="mpg" ;;
    video/mpv) EXT="mpg" ;;
    image/jpeg) EXT="jpg" ;;
    application/vnd.rn-realmedia) EXT="rm" ;;
    video/mp4) EXT="mp4" ;;
    video/quicktime) EXT="qt" ;;
    application/x-zip) EXT="zip" ;;
  *)  case `file -b $file|cut -c -4` in
        RIFF) EXT="avi" ;;
        Micr) EXT="asf" ;;
	*)
           echo -e "`basename $file` has unknown format `file -b $file`\n--\n"
           continue
	;;
      esac
  ;;
  esac

  if [ "`echo $file|sed "s/^.*\.\(.*$\)/\1/"`" != "$EXT" ]; then
    echo "`basename $file` extension does not match format type $EXT"
    fixed=`echo $file|sed "s/\(^.*\.\).*$/\1$EXT/"`
    read -p "Rename to `basename $fixed`? " rename < /dev/tty 

    if [ -z "$rename" -o "$rename" = "y" -o "$rename" = "yes" ]; then
      mv -i "$file" "$fixed"
    else
      echo "Not renaming."
    fi
    echo -e "--\n"
  fi

done