Today, I tried to retrieve datas stored in my USB 2.0 external hard drive.
After I plugged it into my MacBook Air 2013 USB port,
I didn't see it show up in the sidebar of the finder.
So I searching the web to find the solution.

I find two existed softwares to help Mac user using the NTFS disk:

1. Paragon NTFS
   After I installed it, it just can't read my NTFS external hard drive.
   (The disk select list of Paragon NTFS is empty)

2. Tuxera NTFS
   I didn't try it. After I saw it only have 15 days trial version, I just skipped it.

Here are the tips to mount the Windows NTFS filesystem on Mac OSX using command line:

1. Install ntfs-3g

I installed it by using homebrew. If you already installed homebrew as well,
just type brew install ntfs-3g
or you can get the source code of ntfs-3g here

2. Load the fuse4x kernel extension

After installed ntfs-3g, you neet to load the fuse4x-kext or ntfs-3g will not work.
follow the instructions given by brew info fuse4x-kext

sudo /bin/cp -rfX /usr/local/Cellar/fuse4x-kext/0.9.2/Library/Extensions/fuse4x.kext /Library/Extensions

sudo chmod +s /Library/Extensions/fuse4x.kext/Support/load_fuse4x

3. Check & Mount NTFS

diskutil list to see the identifier of your NTFS disk. (for me, it's /dev/disk1s1 here.)

diskutil unmount /dev/disk1s1 (to make sure that the volume is unmounted)

sudo mkdir /Volumes/NTFS (/Volumes/NTFS could be change to anywhere you want to mount your NTFS)

sudo ntfs-3g /dev/disk1s1 /Volumes/NTFS
You can go to check the /Volumes/NTFS if the NTFS is mounted succefully or not.

Unsolved Problem:
All I could see in my NTFS filesystem are directories.
All the files in the directories can't be seen in the finder with gui mode.
So, I just use iTerm2 to cd into the directory, then
open x.pdf to open the file with default application.

References

fuse4x installs properly but kext doesn't get loaded (10.8)
Mount NTFS Drives on Mac