Welcome

Precize is a simple app for obtaining extensive information about any file, folder or bundle, including its true size, inode data, and Bookmark information. It also lets you locate and preview any item using its Bookmark, and displays internal information stored in Finder Aliases and Bookmarks.

macOS allows files to consist of two parts: the normal data fork, and an unlimited number of extended attributes (xattrs), which contain metadata of various types. The xattrs are normally (in HFS+ and APFS file systems) stored in the file system metadata rather than with the data fork, but in some file systems such as ExFAT they are stored in hidden files.

When the Finder reports a file’s size, it only gives the size of its data fork. The same is also true of the ls command in Terminal, unless you use its @ option to list xattrs. In most cases, the total stored in xattrs is small, less than 1 Kbyte, but in extreme cases the total size of the xattrs can be larger than that of the data fork.

Precize addresses the problem of obtaining a full measure of any file’s size, by providing the size of its data fork, the total of its xattrs, and the sum of those. At first sight, it might appear that macOS is capable of doing that itself, using a URLResourceKey claimed by Apple to include “metadata”. Precize also provides the figures given in URLResourceKeys for comparison. You will quickly discover that Apple’s “metadata” excludes almost all xattrs, so is of little or no value.

I initially wrote Precize to look at this problem, and the figures available from macOS. In addition to providing the only full measure of file sizes, it demonstrates that macOS doesn’t appear to know the total size of any of its files. Even in Big Sur running on APFS. This is further complicated by sparse files, which are largely empty and can be stored in a special form on APFS which greatly reduces the disk space used. Precize now shows the disk space used to store the data fork of the file, so you can discover sparse files, and it indicates which are sparse files, which are purgeable, and which may be clones.

Precize also provides information about files and folders which is not widely available except in Terminal, in the attributes associated with the item’s inode. These include its permissions, file type, listings of all its extended attributes, and the inode numbers for the file and the volume on which it is located.

Its Bookmark Resolver window will resolve Finder Alias and Bookmark files and data whenever possible, and provides full details of their internal data.

➜ about references to files and folders

➜ get sizes, inode, and other information about a file or folder

➜ copy a value quickly

➜ resolve a Bookmark

➜ more details

➜ updates

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