R: Shell-style Tests on Files

file_test {utils}

R Documentation

Shell-style Tests on Files

Description

Utility for shell-style file tests.

Usage

file_test(op, x, y)

Arguments

op

a character string specifying the test to be performed. Unary tests (only x is used) are "-f" (existence and not being a directory), "-d" (existence and directory) and "-x" (executable as a file or searchable as a directory). Binary tests are "-nt" (strictly newer than, using the modification dates) and "-ot" (strictly older than): in both cases the test is false unless both files exist.

x,y

character vectors giving file paths.

Details

‘Existence’ here means being on the file system and accessible by the stat system call (or a 64-bit extension) – on a Unix-alike this requires execute permission on all of the directories in the path that leads to the file, but no permissions on the file itself.

For the meaning of "-x" on Windows see file.access.

Examples

dir <- file.path(R.home(), "library", "stats")
file_test("-d", dir)
file_test("-nt", file.path(dir, "R"), file.path(dir, "demo"))