| bk1 | bk2 | bk3 | bkf | bkg |
| bkp | bks | blg | blk | bmd |
| bme | bmi | bmk | bmp | bms |
| bmx | bok | book | bootskin | bot |
| box | bpl | bqy | brf | brx |
| bs | bs_ | bs1 | bsc | bsp |
| bt | bt! | btb | btm | btn |
| btr | bud | bun | bup | bw |
| bwa | bwt | bwv | byu | bz |
| bz2 | c | c00 | c01 | c02 |
| c03 | c04 | c05 | c06 | c07 |
| c08 | c09 | c10 | c11 | c12 |
| c13 | c14 | c15 | c16 | c17 |
| c18 | c19 | c20 | c21 | c22 |
| c23 | c24 | c25 | c26 | c27 |
| c28 | c29 | c2r | c30 | c31 |
| c32 | c33 | c34 | c35 | c36 |
| c37 | c38 | c39 | c3d1 | c3d12 |
| c3d2 | c40 | c41 | c42 | c43 |
| c44 | c45 | c46 | c47 | c48 |
| c49 | c50 | c51 | c52 | c53 |
| c54 | c55 | c56 | c57 | c58 |
| c59 | c60 | c61 | c62 | c63 |
| c64 | c65 | c66 | c67 | c68 |
| 文件扩展名 是操作系统用来标志文件格式的一种机制。通常来说，一个扩展名是跟在文件名后面的，由一个分隔符分隔。在一个像“readme.txt”的文件名中，readme是文件名，txt为扩展名，表示这个文件是一个纯文本文件。 |