GNU Info
(guile.info)File System
File System
===========
These procedures allow querying and setting file system attributes
(such as owner, permissions, sizes and types of files); deleting,
copying, renaming and linking files; creating and removing directories
and querying their contents; syncing the file system and creating
special files.
- primitive: access? path how
Returns `#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.
- primitive: stat object
Returns an object containing various information about the file
determined by OBJ. OBJ 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.
- primitive: 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.
- primitive: readlink path
Returns the value of the symbolic link named by PATH (a string),
i.e., the file that the link points to.
- primitive: 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. The return
value is unspecified.
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.
- primitive: chmod object mode
Changes the permissions of the file referred to by OBJ. OBJ 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)'. The
return value is unspecified.
- primitive: utime pathname [actime [modtime]]
`utime' sets the access and modification times for the file named
by PATH. 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.
E.g.,
(utime "foo" (- (current-time) 3600))
will set the access time to one hour in the past and the
modification time to the current time.
- primitive: delete-file str
Deletes (or "unlinks") the file specified by PATH.
- primitive: copy-file oldfile newfile
Copy the file specified by PATH-FROM to PATH-TO. The return value
is unspecified.
- primitive: rename-file oldname newname
Renames the file specified by PATH-FROM to PATH-TO. The return
value is unspecified.
- primitive: link oldpath newpath
Creates 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.
- primitive: symlink oldpath newpath
Create a symbolic link named PATH-TO with the value (i.e.,
pointing to) PATH-FROM. The return value is unspecified.
- primitive: mkdir path [mode]
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.
The return value is unspecified.
- primitive: rmdir path
Remove the existing directory named by PATH. The directory must
be empty for this to succeed. The return value is unspecified.
- primitive: opendir dirname
Open the directory specified by PATH and return a directory stream.
- primitive: directory-stream? obj
Returns a boolean indicating whether OBJECT is a directory stream
as returned by `opendir'.
- primitive: readdir port
Return (as a string) the next directory entry from the directory
stream STREAM. If there is no remaining entry to be read then the
end of file object is returned.
- primitive: rewinddir port
Reset the directory port STREAM so that the next call to `readdir'
will return the first directory entry.
- primitive: closedir port
Close the directory stream STREAM. The return value is
unspecified.
- primitive: sync
Flush the operating system disk buffers. The return value is
unspecified.
- primitive: mknod path type perms dev
Creates 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.
E.g.,
(mknod "/dev/fd0" 'block-special #o660 (+ (* 2 256) 2))
The return value is unspecified.
- primitive: tmpnam
Create a new file in the file system with a unique name. The
return value is the name of the new file. This function is
implemented with the `tmpnam' function in the system libraries.
- primitive: dirname filename
- primitive: basename filename [suffix]
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