#  `import_streams`

Import and apply modified content streams
## Usage
> pdftl `<input>` `import_streams` `[normalize=true]` `<stream_file>` `output` `<output>`

## Details
The `import_streams` operation reads a text file containing PDF content
streams and applies them directly into the target PDF document.

It is designed to perfectly round-trip the output from [`dump_streams`](<dump_streams.md>).
The primary workflow is to dump a document's streams to text, use standard
Unix text tools (like `sed`, `awk`, or manual text editing) to modify the
PDF operators, and then pipe the resulting text file back into `pdftl`
using `import_streams`.

### Addressing Mechanism
The operation strictly targets semantic paths described in the headers,
ignoring any internal Object IDs (`(4:0)`).
* `=== Page 1 / Contents` overwrites the main content stream of Page 1.
* `=== Page 2 / XObject /Fm1` overwrites the stream of the XObject mapped as
  `/Fm1` within Page 2's resources.
* `=== Page 1 / XObject /Fm1 / XObject /Fm0` overwrites the nested XObject `/Fm0`.

Because it relies on semantic paths, you can easily use text tools to
migrate streams across entirely different PDF documents by simply swapping
the header paths (e.g. using `sed` to rename the target XObject).

### Options
* `normalize=true` (default) — Before writing the stream into the PDF,
  `pdftl` uses `pikepdf`'s internal engine to parse and normalize the syntax.
  This automatically strips any `%` comments (such as those generated by
  `dump_streams annotate`), cleans up whitespace, and validates the PDF syntax.
  Pass `normalize=false` if you want to force raw text byte injection.
## Examples

> Dump, patch, and re-import Page 1's content stream using a Unix pipe
```
pdftl in.pdf dump_streams 1 | sed -e 's/Apple/Banana/' | pdftl in.pdf import_streams - output out.pdf
```

> Apply modifications from a saved text file back into the document
```
pdftl in.pdf import_streams patched_streams.txt output out.pdf
```

> Inject stream text verbatim, without parsing or stripping comments
```
pdftl in.pdf import_streams normalize=false streams.txt output out.pdf
```


**Tags**: in_place, content_stream, dangerous

*Source: pdftl.operations.import_streams*

*Read online: [https://pdftl.readthedocs.io/en/stable/operations/import_streams.html](https://pdftl.readthedocs.io/en/stable/operations/import_streams.html)*

*Type: Operation*