You are almost there:
Instead of mv video.mp4 VIDFOLDER you need to mv video.mp4 "$VIDFOLDER". The $ is needed to use the variable. It must NOT be used during assignement of the variable.
export VIDFOLDER=/path/to/my/folder should go into your .bashrc-file.
As an alternative, you could set up function for that (in .bashrc or .bash_aliases):
vidmv () {
local videos="${@?need a file, please!}"
local vidfolder=/path/to/my/folder
for video in $videos ; do
if [ -r "$video" ] ; then
mv "$video" "$vidfolder"
else
printf '%s\n' "Can't read file \"$video\""
fi
done
}
and call that with vidmv somefile.mp4 or vidmv *.mp4 to move all .mp4 in, see the current directory.function provided by cas