pdfsh 2024.4

minimal shell to investigate PDF files

pdfsh

pdfsh is a utility to investigate the PDF file structure in a shell-like interface. It allows one to "mount" a PDF file and use a simple shell-like interface to navigate inside the PDF file structurally.

Technically, pdfsh is a PDF processor, a PDF reader, but not a viewer that renders the page contents.

In pdfsh, similar to a file system, the PDF file is represented as a tree. All the nodes of the tree are PDF objects.

pdfsh has its own ISO 32000-2:2020 PDF-2.0 parser.

pdfsh uses ccitt and lzw filter implementations and png predictor implementation in pdfminer.six. To minimize the dependency, I decided to add the implementations of these directly to the pdfsh code, so there is no dependency to pdfminer.six.

pdfsh assumes it is run under a ANSI capable terminal as it uses ANSI terminal features and colors. If strange behavior is observed, make sure the terminal emulation it is run is ANSI compatible.

Usage

pip install pdfsh

which installs a pdfsh executable into the path.

When pdfsh is run as pdfsh <pdf_file>, the shell interface is loaded with the document at the root of structural tree. The root node has no name, and represented by a single /.

pdfsh shell interface have commands like ls, cd and cat. For paths, an autocomplete mechanism is implemented.

pdfsh has a simple prompt: <filename>:<current_node> $. The current node is given as a path separated by / like a UNIX filesystem path.

Tutorial

For an introduction to PDF and a tutorial using pdfsh, please see my blog post A Minimum Complete Tutorial of Portable Document Format (PDF) with pdfsh.

Notes

pdfsh supports both cross-reference tables and cross-reference streams as well as hybrid-reference files. However, because pdfsh eagerly constructs the cross-reference table, either the cross-reference table or cross-reference stream is read in a particular update section. Thus, an object that is not visible in cross-reference stream but visible in cross-reference table cannot be found. More information about this topic can be found in ISO 32000-2:2020 7.5.8.4. Compatibility with applications that do not support compressed reference streams.

Changes

Version numbers are in <year>.<positive_integer> format. The <positive_integer monotonically increases in the same year but resets to 1 in the new year.

2024.4

• cross-reference streams support
• object streams support
• --version option added
• migrated from setup.py to pyproject.toml

2024.3 is skipped

2024.2

• first public release

2024.1

• initial test release, not for public use

External Licenses

pdfminer.six

pdfminer.six: Copyright (c) 2004-2016 Yusuke Shinyama <yusuke at shinyama dot jp>

• ccitt.py and lzw.py are part of pdfminer.six
• utils.py contains one function (apply_png_predictor) from the same source file (utils.py) from pdfminer.six.

License

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see https://www.gnu.org/licenses/.