create_symlink.sh

#!/bin/sh

FILE_BASE=foo
SOURCE_FOLDER=/home/wose/tmp/sascha_link/source
TARGET_LINK=/home/wose/tmp/sascha_link/target/foo

HIGHEST_NUMBER=$(find "$SOURCE_FOLDER" -name "*$FILE_BASE*" | sed -r 's/.*\.([0-9]+$)/\1/' | sort -n | tail -n 1)

TARGET_FILE=$(find "$SOURCE_FOLDER" -name "$FILE_BASE.$HIGHEST_NUMBER")

if [ -f $TARGET_LINK ];
then
    rm $TARGET_LINK
fi

ln -s $TARGET_FILE $TARGET_LINK