This module provides additional operations on files. This covers both more obscure and possible non-portable low-level operations and high-level utilities.
Using these Prolog primitives is typically to be preferred over using operating system primitives through shell/1 or process_create/3 because (1) there are no potential file name quoting issues, (2) there is no dependency on operating system commands and (3) using the implementations from this library is usually faster.
- set_time_file(+File, -OldTimes, +NewTimes) is det
- Query and set POSIX time attributes of a file. Both OldTimes and
NewTimes are lists of option-terms. Times are represented in
SWI-Prolog's standard floating point numbers. New times may be
nowto indicate the current time. Defined options are:
- Describes the time of last access of the file. This value can be read and written.
- Describes the time the contents of the file was last modified. This value can be read and written.
- Describes the time the file-structure itself was changed by
link()) or removing (
Below are some example queries. The first retrieves the access-time, while the second sets the last-modified time to the current time.
?- set_time_file(foo, [access(Access)], ). ?- set_time_file(foo, , [modified(now)]).
- link_file(+OldPath, +NewPath, +Type) is det
- Create a link in the filesystem from NewPath to OldPath. Type
defines the type of link and is one of
With some limitations, these functions also work on Windows. First of all, the unerlying filesystem must support links. This requires NTFS. Second, symbolic links are only supported in Vista and later.
- relative_file_name(+Path:atom, +RelTo:atom, -RelPath:atom) is det
- relative_file_name(-Path:atom, +RelTo:atom, +RelPath:atom) is det
- True when RelPath is Path, relative to RelTo. Path and RelTo are
first handed to absolute_file_name/2, which makes the absolute
and canonical. Below are two examples:
?- relative_file_name('/home/janw/nice', '/home/janw/deep/dir/file', Path). Path = '../../nice'. ?- relative_file_name(Path, '/home/janw/deep/dir/file', '../../nice'). Path = '/home/janw/nice'.
- directory_file_path(+Directory, +File, -Path) is det
- directory_file_path(?Directory, ?File, +Path) is det
- True when Path is the full path-name for File in Dir. This is
atom_concat(Directory, File, Path), but it ensures there is exactly one / between the two parts. Notes:
- copy_file(From, To) is det
- Copy a file into a new file or directory. The data is copied as binary data.
- make_directory_path(+Dir) is det
- Create Dir and all required components (like mkdir -p). Can raise various file-specific exceptions.
- copy_directory(+From, +To) is det
- Copy the contents of the directory From to To (recursively). If To is the name of an existing directory, the contents of From are copied into To. I.e., no subdirectory using the basename of From is created.
- delete_directory_and_contents(+Dir) is det
- Recursively remove the directory Dir and its contents. If Dir is a symbolic link or symbolic links inside Dir are encountered, the links are removed rather than their content. Use with care!
- delete_directory_contents(+Dir) is det
- Remove all content from directory Dir, without removing Dir itself. Similar to delete_directory_and_contents/2, if symbolic links are encountered in Dir, the links are removed rather than their content.