Hex Viewer

How to use the hex viewer

1. Choose any file.
2. Read the dump, or search for text or a byte sequence.
3. Page through if the file is longer than one screen.

About this tool

Shows a file exactly as it is stored: sixteen bytes per line, with the offset on the left and the printable characters on the right. It is the tool for answering what a file really contains when nothing else will open it.

Bytes outside the printable ASCII range appear as full stops in the text column. That is the long-standing convention and it is not laziness — rendering a control character literally would move the cursor, ring the terminal bell or emit nothing at all, destroying the column alignment that makes a hex dump readable in the first place.

The search accepts either text or a byte sequence in hex, which covers the two things people actually look for: a string buried in a binary, or a specific signature. Searching for `ff d8 ff` finds the start of a JPEG; searching for readable text finds strings a program has embedded.

Only the first two megabytes are loaded. Reading a four-gigabyte file entirely into memory to display one screenful would achieve nothing except exhausting the tab, and file headers — the part almost anyone examining a file actually wants — live at the very start.

This views but does not edit. Writing bytes back is a different and considerably more dangerous operation.

Common uses

• Checking a file's magic bytes when the extension looks wrong.
• Finding readable strings inside a binary.
• Inspecting a file format while writing a parser.

Frequently asked questions

Why are most characters shown as dots?

Anything outside printable ASCII is shown as a dot by convention. Rendering control characters literally would break the column alignment that makes the dump readable.

Can I edit the bytes?

No. This views only. Writing bytes back to a file is a considerably more dangerous operation and needs a real hex editor.

Why is only part of a large file shown?

The first two megabytes are loaded. Reading a multi-gigabyte file entirely into memory to show one screen would exhaust the tab, and headers live at the start anyway.