tar: Ignoring unknown extended header keyword

After creating a tar archive on macOS and extracting on CentOS/Linux, you may see: tar: Ignoring unknown extended header keyword LIBARCHIVE.xattr.com.apple.metadata:kMDItemTextContentLanguage. This is due to differences in macOS tar. Notes below.

Problem

On macOS, create the archive:

tar -czvf  ../xxxx.tar.gz --exclude='.DS_Store' xxxx/*

On CentOS, extract:

tar -C xx/lib -xz

You’ll see output like:

tar: Ignoring unknown extended header keyword LIBARCHIVE.xattr.com.apple.metadata:kMDItemTextContentLanguage

Why

1. macOS uses BSD tar and writes xattr headers. CentOS commonly uses GNU tar.
2. The message is informational; extraction still works.

Fix

Install GNU tar on macOS: brew install gnu-tar, then create with gtar -czvf ../xxxx.tar.gz --exclude='.DS_Store' xxxx/*.

References

• https://stackoverflow.com/questions/51655657/tar-ignoring-unknown-extended-header-keyword-libarchive-xattr-security-selinux