file_test
Shell-style Tests on Files

### Description

Tests files or directories in a shell-style.

### Usage

    file_test(op, x, y)

### Arguments

op | a character string specifying the operation of test style on files. The supported unary tests are:
"-f" | tests the existence of x and if it is a file.fs.
"-d" | tests the existence of x and if it is a directory.
"-x" | tests the execute permission of x.
The supported binary tests are:
"-nt" | tests the existence of x and y, and if the modified time of x is newer than the one of y.
"-ot" | tests the existence of x and y, and if the modified time of x is older than the one of y.
x | a character string specifying the file or directory path. Required.
y | a character string specifying the second file or directory path. Required for binary tests only.

### Details

This utility function is implemented for shell-style tests on files or directories. Unsupported tests cause the function to stop with an error message.
Value
returns a logical value. If TRUE, the test is successful. Otherwise, returns FALSE.
See Also
file.access, file.info
Examples

    file_test("-f", .libPaths()[1])  # FALSE
    file_test("-f", file.path(.libPaths()[1], "stats", "DESCRIPTION")) # TRUE
    file_test("-d", .libPaths()[1])  # TRUE
    file_test("-x", .libPaths()[1])  # TRUE
    # Test if the modified time of package "utils" is older than "stats"
    file_test("-ot", file.path(.libPaths()[1], "utils"), file.path(.libPaths()[1], "stats"))
    # Unsupported test causes a stop with message "test 'foo' is not available"
    file_test("foo", .libPaths()[1])

Package utils version 6.1.5-18
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