# R: Wildcard Expansion on File Paths

Sys.glob {base} | R Documentation

## Wildcard Expansion on File Paths

### Description

Function to do wildcard expansion (also known as ‘globbing’) on file paths.

Not all platforms support this.

### Usage

    Sys.glob(paths, dirmark = FALSE)

### Arguments

`paths` | character vector of patterns for relative or absolute filepaths.
`dirmark` | logical: should matches to directories from patterns that do not already end in `/` have a slash appended? May not be supported on all platforms.

### Details

This expands wildcards in file paths. For precise details, see your system's documentation on the `glob` system call. There is a POSIX 1003.2 standard (see http://www.opengroup.org/onlinepubs/009695399/functions/glob.html) but some OSes will go beyond this (in particular some BSD-based OSes also do tilde expansion, see `path.expand`).

All systems should interpret `*` (match one of more characters), `?` (match a single character) and `[` (begin a character class or range). If a filename starts with `.` this must be matched explicitly. Normally paths ending in `/` will be accepted and matched only to directories.

The rest of these details are indicative (and based on the POSIX standard).

`[` begins a character class. If the first character in `[...]` is not `!`, this is a character class which matches a single character against any of the characters specified. The class cannot be empty, so `]` can be included provided it is first. If the first character is `!`, the character class matches a single character which is none of the none of the specified characters.

Character classes can include ranges such as `[A-Z]`: include `-` as a character by having it first or last in a class. (The interpretation of ranges should be locale-specific.)

One can remove the special meaning of `?`, `*` and `[` by preceding them by a backslash (except within a character class).

### Value

A character vector of matched file paths. The order is system-specific (but in the order of the elements of `paths`): it is normally collated in the current locale or in byte (ASCII) order.
Directory errors are normally ignored, so the matches are to accessible file paths (but not necessarily accessible files).
On platforms which do not have the `glob` system call, `paths` is returned unchanged.

### See Also

`path.expand`.

Quotes for handling backslashes in character strings.

### Examples

    ## Not run:
    Sys.glob(file.path(R.home(), "library", "*", "R", "*.rdx"))
    ## End(Not run)

[Package base version 2.6.0 Index]