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R.utils (version 1.6.4)

fileAccess: Checks the permission of a file or a directory

Description

Checks the permission of a file or a directory.

Usage

## S3 method for class 'default}(pathname, mode=0, safe=TRUE, ...)':
fileAccessundefined

pathname{A character string of the file or the directory
      to be checked.}
  mode{An integer (0,1,2,4), cf. file.access().}
  safe{If TRUE, the permissions are tested more carefully,
      otherwise file.access() is used.}
  ...{Not used.}

Returns an integer; 0 if the permission exists, -1 if not.

[object Object]


In Rthere is file.access() for checking whether the
  permission of a file.
  Unfortunately, that function cannot be 100% trusted depending on
  platform used and file system queried, cf. [1].


# - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Current directory
# - - - - - - - - - - - - - - - - - - - - - - - - - - - -
path <- "."

# Test for existence
print(fileAccess(path, mode=0))
# Test for execute permission
print(fileAccess(path, mode=1))
# Test for write permission
print(fileAccess(path, mode=2))
# Test for read permission
print(fileAccess(path, mode=4))


# - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# A temporary file
# - - - - - - - - - - - - - - - - - - - - - - - - - - - -
pathname <- tempfile()
cat(file=pathname, "Hello world!")

# Test for existence
print(fileAccess(pathname, mode=0))
# Test for execute permission
print(fileAccess(pathname, mode=1))
# Test for write permission
print(fileAccess(pathname, mode=2))
# Test for read permission
print(fileAccess(pathname, mode=4))

file.remove(pathname)


# - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# The 'base' package directory
# - - - - - - - - - - - - - - - - - - - - - - - - - - - -
path <- system.file(package="base")

# Test for existence
print(fileAccess(path, mode=0))
# Test for execute permission
print(fileAccess(path, mode=1))
# Test for write permission
print(fileAccess(path, mode=2))
# Test for read permission
print(fileAccess(path, mode=4))


# - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# The 'base' package DESCRIPTION file
# - - - - - - - - - - - - - - - - - - - - - - - - - - - -
pathname <- system.file("DESCRIPTION", package="base")

# Test for existence
print(fileAccess(pathname, mode=0))
# Test for execute permission
print(fileAccess(pathname, mode=1))
# Test for write permission
print(fileAccess(pathname, mode=2))
# Test for read permission
print(fileAccess(pathname, mode=4))

file.access()

[1] R-devel thread
     file.access() on network (mounted) drive on Windows Vista?
     on Nov 26, 2008.
[2] Filesystem permissions, Wikipedia, 2010.
     http://en.wikipedia.org/wiki/Filesystem_permissions



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Arguments