file.create(..., showWarnings = TRUE)
file.exists(...)
file.remove(...)
file.rename(from, to)
file.append(file1, file2)
file.copy(from, to, overwrite = recursive, recursive = FALSE, copy.mode = TRUE)
file.symlink(from, to)
file.link(from, to) windows
Sys.junction(from, to)file.copy and file.symlink
windows
and Sys.junction
to can alternatively be the path to a single existing directory.to is a directory, should
directories in from be copied (and their contents)? (Like
cp -R on POSIX OSes.)showWarnings = TRUE, file.create will give a warning
for an unexpected failure.
... arguments are concatenated to form one character
string: you can specify the files separately or as one vector.
All of these functions expand path names: see path.expand. file.create creates files with the given names if they do not
already exist and truncates them if they do. They are created with
the maximal read/write permissions allowed by the
‘umask’ setting (where relevant). By default a warning
is given (with the reason) if the operation fails.
file.exists returns a logical vector indicating whether the
files named by its argument exist. (Here ‘exists’ is in the
sense of the system's stat call: a file will be reported as
existing only if you have the permissions needed by stat.
Existence can also be checked by file.access, which
might use different permissions and so obtain a different result.
Note that the existence of a file does not imply that it is readable:
for that use file.access.) What constitutes a
‘file’ is system-dependent, but should include directories.
(However, directory names must not include a trailing backslash or
slash on Windows.) Note that if the file is a symbolic link on a
Unix-alike, the result indicates if the link points to an actual file,
not just if the link exists.
Lastly, note the different function exists which
checks for existence of R objects.
file.remove attempts to remove the files named in its argument.
On most Unix platforms ‘file’ includes empty
directories, symbolic links, fifos and sockets. On Windows,
‘file’ means a regular file and not, say, an empty directory.
file.rename attempts to rename files (and from and
to must be of the same length). Where file permissions allow
this will overwrite an existing element of to. This is subject
to the limitations of the OS's corresponding system call (see
something like man 2 rename on a Unix-alike): in particular
in the interpretation of ‘file’: most platforms will not rename
files across file systems. (On Windows, file.rename can move
files but not directories between volumes.) On platforms which allow
directories to be renamed, typically neither or both of from
and to must a directory, and if to exists it must be an
empty directory.
file.append attempts to append the files named by its
second argument to those named by its first. The R subscript
recycling rule is used to align names given in vectors
of different lengths.
file.copy works in a similar way to file.append but with
the arguments in the natural order for copying. Copying to existing
destination files is skipped unless overwrite = TRUE. The
to argument can specify a single existing directory. If
copy.mode = TRUE file read/write/execute permissions are copied
where possible, restricted by ‘umask’. (On Windows this
applies only to files.) Other security attributes such as ACLs are not
copied. On a POSIX filesystem the targets of symbolic links will be
copied rather than the links themselves, and hard links are copied
separately.
file.symlink and file.link make symbolic and hard links
on those file systems which support them. For file.symlink the
to argument can specify a single existing directory. (Unix and
OS X native filesystems support both. Windows has hard links to
files on NTFS file systems and concepts related to symbolic links on
recent versions: see the section below on the Windows version of this
help page. What happens on a FAT or SMB-mounted file system is OS-specific.)
file.info, file.access, file.path,
file.show, list.files,
unlink, basename,
path.expand. Sys.glob to expand wildcards in file specifications.
http://en.wikipedia.org/wiki/Hard_link and http://en.wikipedia.org/wiki/Symbolic_link for the concepts of links and their limitations.
cat("file A\n", file = "A")
cat("file B\n", file = "B")
file.append("A", "B")
file.create("A")
file.append("A", rep("B", 10))
if(interactive()) file.show("A")
file.copy("A", "C")
dir.create("tmp")
file.copy(c("A", "B"), "tmp")
list.files("tmp")
unix
setwd("tmp")
file.remove("B")
file.symlink(file.path("..", c("A", "B")), ".")
setwd("..")
unlink("tmp", recursive = TRUE)
file.remove("A", "B", "C")
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