files {base}

R Documentation

File Manipulation

Description

These functions provide a low-level interface to the computer's file system.

Usage

file.create(..., showWarnings = TRUE)
file.exists(...)
file.remove(...)
file.rename(from, to)
file.append(file1, file2)
file.copy(from, to, overwrite = recursive, recursive = FALSE)
file.symlink(from, to)

Arguments

..., file1, file2, from, to	character vectors, containing file names or paths.
overwrite	logical; should the destination files be overwritten?
showWarnings	logical; should the warnings on failure be shown?
recursive	logical. If to is a directory, should directories in from be copied (and their contents).

Details

The ... 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 permissions allowed by the umask setting.

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.) Note that if the file is a symbolic link, the result indicates if the libk points to an actual file, not just if the link exists.

file.remove attempts to remove the files named in its argument. On most platforms ‘file’ includes empty directories, symbolic links, fifos and sockets.

file.rename attempts to rename a single file.

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.

file.symlink makes symbolic links on those Unix-like platforms which support them. The to argument can specify a single existing directory.

Value

file.rename returns a logical value, true for success.

The remaining functions return a logical vector indicating which operation succeeded for each of the files attempted. Using a missing value for a file or path name will always be regarded as a failure.

If showWarnings = TRUE, file.create will give a warning for an unexpected failure.

Author(s)

Ross Ihaka, Brian Ripley

See Also

file.info, file.access, file.path, file.show, list.files, unlink, basename, path.expand.

dir.create.

Sys.glob to expand wildcards in file specifications.

file_test.

Examples

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")
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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