My backup solution

bak.sh

#!/bin/sh

for file in $*
do
  path=`dirname $file`
  name=`basename $file`

  if [ `printf "%.1s" $path` = "/" ]
  then
    echo "Files must be specified relative: $file"
    exit 1

  elif [ `printf "%.1s" $path` = "." ]
  then
    path=""

  else
    path="/$path"

  fi

  bu_path="backup$path"
  bu_file="$bu_path/$name.`date +%Y%m%d`"

  if [ ! -d $bu_path ]
  then
    echo "Creating $bu_path"
    mkdir -p "$bu_path"
  fi

  if [ -f $bu_file ] || [ -f "$bu_file.0" ]
  then
    inc=1
    if [ ! -f "$bu_file.0" ]
    then
      mv $bu_file "$bu_file.0"
    fi

    while [ -f "$bu_file.$inc" ]
    do
      inc=$((inc + 1))
    done

    bu_file="$bu_file.$inc"
  fi

  echo "$file => $bu_file"

  cp -pr $file $bu_file
done