names have the access modes
specified by
mode, for example, whether the files exist or are writable.
access(names, mode=0) file.access(names, mode=0)
names vector, it is repeated cyclically. The values
for the elements of
mode are as follows:
mode is a vector of 0s and 2s.)
access returns a numeric vector of length
length(names) consisting of 0s (if the file
has the specified access) and -1s (if the file does not).
The value of
file.access is a named vector: the result
of calling
access then using the value of the
names
argument as the vector's
names attribute.
The
access function is an implementation of the C library function access.
The
file.access function emulates R's function
of the same name.
access("trytoed.it", 2)
# a return value of -1 indicates the file is not writable (it may or
# may not exist)
access("trytoed.it", 0)
# a subsequent return value of 0 indicates that the file exists
# (implying the file is read-only)
# check access mode of two files (one does not exist)
tfile1 <- tempfile("a")
tfile2 <- tempfile("b")
cat("Today's date is:",date(),"\n", file=tfile1)
file.access(c(tfile1,tfile2),mode=4)
unlink(tfile1)