R: Extract File Information

file.info {base} | R Documentation

## Extract File Information

### Description

Utility function to extract information about files on the user's file systems.

### Usage

    file.info(..., extra_cols = TRUE)

    file.mode(...)
    file.mtime(...)
    file.size(...)

### Arguments

`...` | character vectors containing file paths. Tilde-expansion is done: see `path.expand`.
`extra_cols` | Logical: return all cols rather than just the first six.

### Details

What constitutes a ‘file’ is OS-dependent but includes directories. (However, directory names must not include a trailing backslash or slash on Windows.) See also the section in the help for `file.exists` on case-insensitive file systems.

The file ‘mode’ follows POSIX conventions, giving three octal digits summarizing the permissions for the file owner, the owner's group and for anyone respectively. Each digit is the logical or of read (4), write (2) and execute/search (1) permissions.

See files for how file paths with marked encodings are interpreted.

File modes are probably only useful on NTFS file systems, and it seems all three digits refer to the file's owner. The execute/search bits are set for directories, and for files based on their extensions (e.g., ‘.exe’, ‘.com’, ‘.cmd’ and ‘.bat’ files). `file.access` will give a more reliable view of read/write access availability to the R process.

UTF-8-encoded file names not valid in the current locale can be used.

Junction points and symbolic links are followed, so information is given about the file/directory to which the link points rather than about the link.

### Value

For `file.info`, data frame with row names the file names and columns

`size` | double: File size in bytes.
`isdir` | logical: Is the file a directory?
`mode` | integer of class `"octmode"`. The file permissions, printed in octal, for example `644`.
`mtime, ctime, atime` | integer of class `"POSIXct"`: file modification, ‘last status change’ and last access times.

`exe` | character: what sort of executable is this? Possible values are `"no"`, `"msdos"`, `"win16"`, `"win32"`, `"win64"` and `"unknown"`. Note that a file (e.g., a script file) can be executable according to the mode bits but not executable in this sense.

If `extra_cols` is false, only the first six columns are returned: as these can all be found from a single C system call this can be faster. (However, properly configured systems will use a ‘name service cache daemon’ to speed up the name lookups.)

Entries for non-existent or non-readable files will be `NA`.

What is meant by the three file times depends on the OS and file system. On Windows native file systems `ctime` is the file creation time (something which is not recorded on most Unix-alike file systems). What is meant by ‘file access’ and hence the ‘last access time’ is system-dependent.

The times are reported to an accuracy of seconds, and perhaps more on some systems. However, many file systems only record times in seconds, and some (e.g., modification time on FAT systems) are recorded in increments of 2 or more seconds.

`file.mode`, `file.mtime` and `file.size` are convenience wrappers returning just one of the columns.

### See Also

`Sys.readlink` to find out about symbolic links, `files`, `file.access`, `list.files`, and `DateTimeClasses` for the date formats.

`Sys.chmod` to change permissions.

### Examples

    ncol(finf <- file.info(dir()))  # at least six
    finf # the whole list
    ## Those that are more than 100 days old :
    finf <- file.info(dir(), extra_cols = FALSE)
    finf[difftime(Sys.time(), finf[,"mtime"], units = "days") > 100 , 1:4]

    file.info("no-such-file-exists")

[Package base version 4.0.5 Index]