How to export Base64 to a text file on a Mac

The clipboard is fine for a string you are about to paste. It is a poor container for two and a half megabytes of text you want to keep, attach or check into a repository. For that, write a file.

Export a result

1. Encode the file

   Load your image or PDF in Encode (⌘1) as usual.

2. Choose the format and wrapping

   Whatever you pick is what gets written. A plain result can be wrapped at 64 or 76 columns; the wrapping is preserved in the file.

3. Export

   Press ⌘E, or click Export…. Choose a name and a location — somewhere like /Users/you/Documents/payloads/ — and the complete result is written as a .txt file.

When to export rather than copy

• The result is large. Several megabytes through the clipboard is slow and pointless if the destination is a file anyway.
• You want to keep it. A payload you will use again, attach to a ticket, or commit alongside a test.
• Something in between normalises whitespace. Chat clients and web forms rewrite text. A file arrives as it left.
• You want it in a repository. A checked-in fixture is a file, not a paste.

What the file contains

Exactly what the result pane shows: the complete output in the format you chose, with the wrapping you chose, and nothing added. A plain export is only Base64 characters; a data URI export begins with its prefix; an HTML export is the tag.

That matters because the file is round-trippable: drop it back onto Decode and the picture comes back, whichever of the five formats you wrote.

Very large sources

Above a certain size B64 offers to encode straight to a file rather than building the whole result in memory first. Accept it — the bytes are written directly, and nothing has to hold a hundred megabytes of text just so a preview can show you the first screen. See encoding a large image.

Exporting a whole folder at once

Batch (⌘3) writes one text file per source, all into a folder you name, in a single pass — with an optional checksum manifest covering the run. See how to save all batch results to a folder.

Troubleshooting

The exported file looks truncated

It is not — check the size against the character count shown in the app. What you are probably seeing is a viewer that renders only the first part of a very long line.

I need a different extension

The content is plain text whatever it is called. Rename the file afterwards if the destination expects something else.

Where did my export go?

Wherever you pointed the save panel. It defaults to the last place you saved something, which on a first run is usually your Documents folder.