— Scheme Procedure: access? path how
— C Function: scm_access (path, how)

Return #t if path corresponds to an existing file and the current process has the type of access specified by how, otherwise #f. how should be specified using the values of the variables listed below. Multiple values can be combined using a bitwise or, in which case #t will only be returned if all accesses are granted.

Permissions are checked using the real id of the current process, not the effective id, although it's the effective id which determines whether the access would actually be granted.

— Variable: R_OK

Test for read permission.

— Variable: W_OK

Test for write permission.

— Variable: X_OK

Test for execute permission.

— Variable: F_OK

Test for existence of the file.

— Scheme Procedure: stat object
— C Function: scm_stat (object)

Return an object containing various information about the file determined by object. object can be a string containing a file name or a port or integer file descriptor which is open on a file (in which case fstat is used as the underlying system call).

The object returned by stat can be passed as a single parameter to the following procedures, all of which return integers:

stat:dev

The device containing the file.

stat:ino

The file serial number, which distinguishes this file from all other files on the same device.

stat:mode

The mode of the file. This includes file type information and the file permission bits. See stat:type and stat:perms below.

stat:nlink

The number of hard links to the file.

stat:uid

The user ID of the file's owner.

stat:gid

The group ID of the file.

stat:rdev

Device ID; this entry is defined only for character or block special files.

stat:size

The size of a regular file in bytes.

stat:atime

The last access time for the file.

stat:mtime

The last modification time for the file.

stat:ctime

The last modification time for the attributes of the file.

stat:blksize

The optimal block size for reading or writing the file, in bytes.

stat:blocks

The amount of disk space that the file occupies measured in units of 512 byte blocks.

In addition, the following procedures return the information from stat:mode in a more convenient form:

stat:type

A symbol representing the type of file. Possible values are regular, directory, symlink, block-special, char-special, fifo, socket and unknown.

stat:perms

An integer representing the access permission bits.

— Scheme Procedure: lstat str
— C Function: scm_lstat (str)

Similar to stat, but does not follow symbolic links, i.e., it will return information about a symbolic link itself, not the file it points to. path must be a string.

— Scheme Procedure: readlink path
— C Function: scm_readlink (path)

Return the value of the symbolic link named by path (a string), i.e., the file that the link points to.

— Scheme Procedure: chown object owner group
— C Function: scm_chown (object, owner, group)

Change the ownership and group of the file referred to by object to the integer values owner and group. object can be a string containing a file name or, if the platform supports fchown, a port or integer file descriptor which is open on the file.

If object is a symbolic link, either the ownership of the link or the ownership of the referenced file will be changed depending on the operating system (lchown is unsupported at present). If owner or group is specified as -1, then that ID is not changed.

— Scheme Procedure: chmod object mode
— C Function: scm_chmod (object, mode)

Change the permissions of the file referred to by object. object can be a string containing a file name or a port or integer file descriptor which is open on a file (in which case fchmod is used as the underlying system call). mode specifies the new permissions as a decimal number, e.g., (chmod "foo" #o755).

— Scheme Procedure: utime pathname [actime [modtime]]
— C Function: scm_utime (pathname, actime, modtime) |1 |2 |0

Set the access and modification times for the file named by pathname. If actime or modtime is not supplied, then the current time is used. actime and modtime must be integer time values as returned by the current-time procedure. For example,

          (utime "foo" (- (current-time) 3600))

will set the access time to one hour in the past and the modification time to the current time.

— Scheme Procedure: delete-file path
— C Function: scm_delete_file (path)

Delete (or "unlink") the file specified by path.

— Scheme Procedure: copy-file path-from path-to
— C Function: scm_copy_file (path-from, path-to)

Copy the file specified by path-from to path-to.

— Scheme Procedure: rename-file path-from path-to
— C Function: scm_rename (path-from, path-to)

Rename the file specified by path-from to path-to.

— Scheme Procedure: link path-from path-to
— C Function: scm_link (path-from, path-to)

Create a new name path-to in the file system for the file named by path-from. If path-from is a symbolic link, the link may or may not be followed depending on the system.

— Scheme Procedure: symlink path-from path-to
— C Function: scm_symlink (path-from, path-to)

Create a symbolic link named path-to with the value (i.e., pointing to) path-from.

— Scheme Procedure: mkdir path [mode]
— C Function: scm_mkdir (path, mode) |1 |1 |0

Create a new directory named by path. If mode is omitted then the permissions of the directory file are set using the current umask. Otherwise they are set to the decimal value specified with mode.

— Scheme Procedure: rmdir path
— C Function: scm_rmdir (path)

Remove the existing directory named by path. The directory must be empty for this to succeed.

— Scheme Procedure: opendir path
— C Function: scm_opendir (path)

Open the directory specified by path and return a directory stream.

— Scheme Procedure: directory-stream? object
— C Function: scm_directory_stream_p (object)

Return a boolean indicating whether object is a directory stream as returned by opendir.

— Scheme Procedure: readdir stream
— C Function: scm_readdir (stream)

Return (as a string) the next directory entry from the directory stream stream. If there is no remaining entry to be read, return the end-of-file object.

— Scheme Procedure: rewinddir stream
— C Function: scm_rewinddir (stream)

Reset the directory port stream so that the next call to readdir will return the first directory entry.

— Scheme Procedure: closedir stream
— C Function: scm_closedir (stream)

Close the directory stream stream.

— Scheme Procedure: sync
— C Function: scm_sync ()

Flush the operating system disk buffers.

— Scheme Procedure: mknod path type perms dev
— C Function: scm_mknod (path, type, perms, dev)

Create a new special file, such as a file corresponding to a device. path specifies the name of the file. type should be one of the following symbols: regular, directory, symlink, block-special, char-special, fifo, or socket.

perms (an integer) specifies the file permissions. dev (an integer) specifies which device the special file refers to. Its exact interpretation depends on the kind of special file being created. For example,

          (mknod "/dev/fd0" 'block-special #o660 (+ (* 2 256) 2))

— Scheme Procedure: tmpnam
— C Function: scm_tmpnam ()

Return a name in the file system that does not match any existing file. However there is no guarantee that another process will not create the file after tmpnam is called. Care should be taken if opening the file, e.g., use the O_EXCL open flag.

— Scheme Procedure: dirname filename
— C Function: scm_dirname (filename)

Return the directory name component of the file name filename. If filename does not contain a directory component, . is returned.

— Scheme Procedure: basename filename [suffix]
— C Function: scm_basename (filename, suffix) |1 |1 |0

Return the base name of the file name filename. The base name is the file name without any directory components. If suffix is provided, and is equal to the end of basename, it is removed also.