Windows 7 – Start Executables with Space Named Files Without Waiting

I guess the solution to your problem is called parameter substitution (have a look at the detailed description). Given a name of a file in filename you'll get its extension using ${filename##*.} and the name w/o extension with ${filename%.*}.

That said, you may want to modify your for loop like:

# for all (*) files in the current directory
for i in *;
do
    # -f checks if it is a file (skip directories)
    [ -f "$i" ] || continue
    # store the file name in filename
    filename=$(basename $i)
    # ext = the extension of the file (here we don't care, jfi)
    ext="${filename##*.}"
    # dir = the file name without its extension
    dir="${filename%.*}"
    # create the directory
    mkdir -p $dir
    # move the file in that directory
    mv $i $dir
done

Unfortunately, I did not get the point of your bonus task, so it'll remain an open challenge... :)

It sounds like your COMSPEC variable is corrupted. On my Windows 7 machine I have ComSpec=C:\Windows\system32\cmd.exe. A corrupted COMSPEC value will also prevent pipes from working.