file_test               package: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) and '"-d"' (existence and 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.

See Also:

     'file.exists' which only tests for existence ('test -e' on some
     systems) but not for not being a directory.

     'file.path', 'file.info'

Examples:

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

