Tar files made in macOS generate "xattr" errors when expanded in Linux

Dealing with tar files created on macOS that spit out annoying xattr errors when extracted on Linux? This post provides straightforward fixes to prevent the macOS-specific metadata from polluting your archives. It's a classic cross-platform compatibility headache, and the discussion delves into the deeper philosophies behind Apple's tar behavior versus the Unix standard.

Score

Comments

Highest Rank

13h

on Front Page

First Seen

May 4, 12:00 AM

Last Seen

May 4, 12:00 PM

Rank Over Time

The Lowdown

When creating tar archives on macOS and extracting them on a Linux system, developers often encounter warnings or errors related to extended attributes (xattrs) and the creation of ._ files. This behavior stems from macOS's default bsdtar utility, which attempts to faithfully preserve all filesystem metadata, leading to compatibility issues when moved to systems that don't recognize these Apple-specific attributes.

Here are the presented solutions to ensure clean tar files:

Solution 1: Use --no-xattrs: Adding this flag when creating the tar file (tar -cvzf --no-xattrs pix.tar.gz pix) prevents macOS's extended attributes from being included.
Solution 2: Use --disable-copyfile: An alternative flag, --disable-copyfile, achieves a similar outcome by stopping the inclusion of macOS-specific metadata.
Solution 3: Install and Use gnu-tar: For a more permanent solution, one can install gnu-tar via Homebrew and configure their shell to use it as the default tar command, bypassing bsdtar's default behavior entirely.

By adopting one of these methods, developers can avoid the clutter of ._ files and xattr warnings, ensuring smoother cross-platform deployments.

The Gossip

Apple's Archival Aims

Many commentators explain that Apple's default `tar` behavior, driven by `libarchive`, is intended to preserve all filesystem metadata, including Finder and Gatekeeper attributes, ensuring 'fidelity' when archives are round-tripped between Macs. This design choice is framed as Apple treating `tar` less as a 'portable Unix interchange' and more as a tool to 'archive this filesystem object faithfully,' which some argue aligns with the 'principle of least surprise' from an Apple user's perspective, even if it creates friction elsewhere.

Practical Protections & Suppressions

Users offer various practical command-line flags and environmental variables to manage or suppress the `xattr` errors. Common suggestions include using `--no-xattrs` and `--no-mac-metadata` during tar creation, or the `COPYFILE_DISABLE=1` environment variable. Others note that the warnings can often be safely ignored or suppressed by redirecting `stderr` to `/dev/null` or using `--warning=no-unknown-keyword` for a cleaner output, if the integrity of the extracted files isn't compromised.

Metadata Mayhem & Interoperability Ire

The discussion often devolves into broader frustrations with cross-platform interoperability, particularly concerning macOS-specific metadata. Commenters debate whether Linux *should* implement similar metadata tracking and security features, or if the Unix philosophy of simpler, portable archives is preferable. There's also widespread exasperation with `.DS_Store` files and other Apple-specific filesystem pollution, with some wishing for system-wide options to disable them or even automatic unmounting of remote shares that contain them.