What is the INFO file format?
.info files are GNU Info documents - the compiled, node-based hypertext documentation format used by the GNU Project to ship reference manuals with its software. The format was created in 1986 and is the primary documentation mechanism for tools such as bash, grep, gcc, and thousands of other GNU utilities installed on Linux and macOS systems.
A .info file is plain UTF-8 (or ASCII) text structured as a series of nodes separated by the ASCII unit-separator character (0x1F). Each node begins with a tag line identifying its name and navigation links (File:, Node:, Next:, Prev:, Up:), followed by the documentation body. Menus and cross-references create a navigable hypertext system. The files are produced from Texinfo source (.texi) using the makeinfo or texi2any command - edit the source, not the compiled .info directly.
On Linux and macOS, .info files are installed under /usr/share/info/ and commonly stored compressed as .gz archives to save disk space; the info reader decompresses them on the fly. The info command-line tool, pinfo, and GNU Emacs can all navigate them interactively.
While .info remains standard for GNU software documentation, modern projects increasingly supplement or replace it with HTML or online docs. The format is stable and backwards-compatible across GNU Texinfo versions.
Security & safety
RISK: LOWA GNU .info file is plain text documentation - it contains no executable code and poses no security risk. Open it freely. The only caution applies to the Canon/Amiga/ game uses of the .info extension: Canon sidecar files are metadata (harmless), but .info files from unknown game installers should be treated with normal caution for any file from an unverified source.
Format details
in a nutshell- Canon ZoomBrowser EX / Digital Photo Professional information sidecar - Canon imaging software uses .info files as sidecar metadata or catalog metadata alongside image files - unrelated to GNU Info.
- Amiga icon / tooltypes data - Classic AmigaOS stores per-file metadata and icon tooltypes in .info sidecar files alongside every file and drawer - a completely separate binary format.
- Game installer / patch information file - Various game installers and launchers (e.g. Steam, GOG) use .info files as plain-text or JSON-like configuration/manifest files - naming coincidence only.
Programs that open INFO files
Windows3 apps
GNU Emacs (Windows)
Open-source Download Emacs for Windows; M-x info to browse the Info system or open a .info file.
Cygwin / MSYS2 info reader
Open-source Install Cygwin or MSYS2 and the texinfo package; then run 'info' as on Linux.
Any text editor (Notepad++ / VS Code)
Free A .info is plain text; open in any editor to read raw. The 0x1F node separators appear as control characters. 
macOS2 apps
info (via Homebrew or system)
Open-source macOS ships a minimal 'info' command; for full GNU info install via Homebrew ('brew install texinfo'). Run 'info filename'. 
Linux3 apps
GNU Emacs
Open-source M-x info to browse the Info system; C-u M-x info to open a specific .info file. Emacs's Info browser is the most feature-rich.
info (GNU Info reader)
Open-source Run 'info filename' in a terminal, or 'info -f file.info'. Navigate with arrow keys, n/p (next/prev), u (up), q (quit).
pinfo
Open-source A nicer terminal info browser; run 'pinfo filename'. Supports colour and mouse. Install via package manager (apt/dnf: pinfo). Technical details
deep spec| Format type | Plain-text, node-based hypertext documentation (GNU Info format) |
| Encoding | UTF-8 (or ASCII); older files may be ISO-8859-1/Latin-1; charset is not embedded - inferred from locale |
| Node separator | ASCII 0x1F (unit-separator character) on a line by itself marks the boundary between nodes |
| Node header fields | Each node begins with a tag line: File:, Node:, Next:, Prev:, Up: - defining the document navigation graph |
| Source format | Compiled from Texinfo (.texi) source using makeinfo or texi2any; the .info output is generated, not hand-edited |
| MIME type | application/x-info |
| On-disk compression | Commonly distributed and installed as .info.gz (gzip-compressed); the info reader decompresses transparently on the fly |
| Installation path | /usr/share/info/ on Linux and macOS; a top-level dir file serves as the master index, maintained by the install-info utility |
| Typical file size | 5 KB - 5 MB uncompressed; installed .info.gz files typically 10-500 KB |
| Cross-reference syntax | @xref{nodename} in Texinfo source compiles to *Note nodename:: in the .info file; menus use * Item:: notation |
| Multi-file documents | Large manuals split across multiple numbered files (e.g., emacs.info-1, emacs.info-2) with an indirect map in the primary file |
| Platform | Linux, macOS, BSD, Windows (via GNU Emacs, Cygwin, or MSYS2) |
| Preamble line | The first line identifies the file as a generated Info document, naming the source .texi file and the makeinfo version used to compile it |
| Backwards compatibility | The Info node format is stable; newer makeinfo versions can read, update, and regenerate Info files produced by older versions |
| Released | 1986 (GNU Info reader, GNU Texinfo project) |
| Latest version | GNU Texinfo 7.2 (2024); Info format specification in Texinfo 7.x manual |
| Open standard | Yes · royalty-free |
| Specification | www.gnu.org |
INFO conversions
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