Utility function to access information about files on the user's
file systems.
Usage
file.access(names, mode = 0)
Arguments
names
character vector containing file names.
Tilde-expansion will be done: see path.expand.
mode
integer specifying access mode required: see ‘Details’.
Details
The mode value can be the exclusive or of the following values
0
test for existence.
1
test for execute permission.
2
test for write permission.
4
test for read permission.
Permission will be computed for real user ID and real group ID (rather
than the effective IDs).
Please note that it is not a good idea to use this function to test
before trying to open a file. On a multi-tasking system, it is
possible that the accessibility of a file will change between the time
you call file.access() and the time you try to open the file.
It is better to wrap file open attempts in try.
Value
An integer vector with values 0 for success and -1 for failure.
Note
This is intended as a replacement for the S-PLUS function
access, a wrapper for the C function of the same name, which
explains the return value encoding. Note that
the return value is false for success.
See Also
file.info for more details on permissions,
Sys.chmod to change permissions, and
try for a ‘test it and see’ approach.
file_test for shell-style file tests.
Examples
fa <- file.access(dir("."))
table(fa) # count successes & failures
Results
R version 3.3.1 (2016-06-21) -- "Bug in Your Hair"
Copyright (C) 2016 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)
R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type 'license()' or 'licence()' for distribution details.
R is a collaborative project with many contributors.
Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.
Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.
> library(base)
> png(filename="/home/ddbj/snapshot/RGM3/R_rel/result/base/file.access.Rd_%03d_medium.png", width=480, height=480)
> ### Name: file.access
> ### Title: Ascertain File Accessibility
> ### Aliases: file.access
> ### Keywords: file
>
> ### ** Examples
>
> fa <- file.access(dir("."))
> table(fa) # count successes & failures
fa
0
25
>
>
>
>
> dev.off()
null device
1
>