Alias (Mac OS)
In classic Mac OS System 7 and later, and in macOS, an alias is a small file that represents another object in a local, remote, or removable file system and provides a dynamic link to it; the target object may be moved or renamed, and the alias will still link to it (unless the original file is recreated; such an alias is ambiguous and how it is resolved depends on the version of macOS). In Windows, a "shortcut", a file with a .lnk extension, performs a similar function.
| Type code | alis |
|---|---|
| Uniform Type Identifier (UTI) | com.apple.alias-file |
| Magic number | 'book\0\0\0\0mark\0\0\0\0' |
| Developed by | Apple, Inc. |
| Type of format | shortcut |
It is similar to the Unix symbolic link, but with the distinction of working even if the target file moves to another location on the same disk (in this case it acts like a hard link, but the source and target of the link may be on different filesystems, and the target of the link may be a directory). As a descendant of BSD, macOS supports Unix symbolic (and hard) links as well.