Data file
What is a .o file?
A .o file is an Executable and Linkable Format (version 32bit Little Endian). This is a data file — structured information used by a program rather than read directly. Confusingly, this extension has been used by 5 different formats over the years — they're all listed below.
This extension has been used by more than one format
5 different formats have claimed .o over the years, so two files with the same extension aren't necessarily the same kind of thing.
- Executable and Linkable FormatVersion 32bit Little Endian · fmt/688
- Executable and Linkable FormatVersion 32bit Big Endian · fmt/689
- Executable and Linkable FormatVersion 64bit Little Endian · fmt/690
- Executable and Linkable FormatVersion 64bit Big Endian · fmt/691
- Linux/i386 Binary Executable File ZMAGICNo version recorded · fmt/1672
How to open a .o file
- Start with the program that produced it; that's almost always the right tool.
- Open it in a text editor to see whether it's readable text or binary.
- For database formats, DB Browser for SQLite or LibreOffice Base can often import it.
The registry records this extension against Executable and Linkable Format, Executable and Linkable Format, Executable and Linkable Format and others, so software from that family is the most likely match.
How to convert a .o file
- If you can view the data, exporting to .csv is usually the most portable option.
The technical record
For archivists, developers and the merely curious: these are the PRONOM registry entries for .o.
| Format name | Version | MIME type | PUID |
|---|---|---|---|
| Executable and Linkable Format | 32bit Little Endian | — | fmt/688 |
| Executable and Linkable Format | 32bit Big Endian | — | fmt/689 |
| Executable and Linkable Format | 64bit Little Endian | — | fmt/690 |
| Executable and Linkable Format | 64bit Big Endian | — | fmt/691 |
| Linux/i386 Binary Executable File ZMAGIC | — | — | fmt/1672 |