# Viewing with Hex Editor

In order to analyze the file system, we have to view it using hexadecimal editor.

There are two common hex editors in Ubuntu:

* hexedit
* xxd

Now try to view the disk file by hexedit. If you haven't unmount it, do it now.

In the terminal,

```
$ hexedit test.disk
```

![](/files/-Lp-5bN3bv52RU6TI9G3)

There are three columns in the output:

1. Line number in hexadecimal
2. Content in Hexadeciaml
3. Content in ASCII

For one hex digit, 4 bits (2^4 = 16) are needed to represent 0-15(0-F). Two hex digits occipies 8bits = 1 byte, therefore they are in group of two.


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