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file-author

file-author Function

Syntax:

file-author pathspec → author

Arguments and Values:

pathspec—a pathname designator .

author—a string or nil.

Description:

Returns a string naming the author of the file specified by pathspec, or nil if the author’s name cannot be determined.

Examples:

(with-open-file (stream ">relativity>general.text") 
  (file-author s)) 
→ "albert"

Affected By:

The host computer’s file system.

Other users of the file named by pathspec.

Exceptional Situations:

An error of type file-error is signaled if pathspec is wild.

An error of type file-error is signaled if the file system cannot perform the requested operation.

See Also:

pathname, logical-pathname, Section 20.1 (File System Concepts), Section 19.1.2 (Pathnames as Filenames)

Expanded Reference: file-author​

Querying the author of a file​

file-author returns a string naming the author of the specified file, or nil if the author cannot be determined. Support for file authorship is implementation-dependent and file-system-dependent.

;; On many Unix systems, file-author returns the owner's login name
(with-open-file (s "/tmp/cl-author-test.txt" :direction :output
                   :if-exists :supersede)
  (write-string "test" s))

(file-author "/tmp/cl-author-test.txt")
;; => "username"  ; implementation-dependent

Result type is string or nil​

The return value is always either a string or nil. Many modern file systems do not track authorship separately from ownership.

(let ((author (file-author "/tmp/cl-author-test.txt")))
  (or (stringp author) (null author)))
=> T

Accepts pathname designators​

Like most file functions, file-author accepts strings, pathnames, and streams as its argument.

(file-author #P"/tmp/cl-author-test.txt")
;; => "username"  ; implementation-dependent

(with-open-file (s "/tmp/cl-author-test.txt")
  (file-author s))
;; => "username"  ; implementation-dependent