fs_perms {fs}

Create, modify and view file permissions

Description

fs_perms() objects help one create and modify file permissions easily. They support both numeric input, octal and symbolic character representations. Compared to octmode they support symbolic representations and display the mode the same format as ls on POSIX systems.

Usage

as_fs_perms(x, ...)

fs_perms(x, ...)

Arguments

x

An object which is to be coerced to a fs_perms object. Can be an number or octal character representation, including symbolic representations.

...

Additional arguments passed to methods.

Details

On POSIX systems the permissions are displayed as a 9 character string with three sets of three characters. Each set corresponds to the permissions for the user, the group and other (or default) users.

If the first character of each set is a "r", the file is readable for those users, if a "-", it is not readable.

If the second character of each set is a "w", the file is writable for those users, if a "-", it is not writable.

The third character is more complex, and is the first of the following characters which apply.

• 'S' If the character is part of the owner permissions and the file is not executable or the directory is not searchable by the owner, and the set-user-id bit is set.

• 'S' If the character is part of the group permissions and the file is not executable or the directory is not searchable by the group, and the set-group-id bit is set.

• 'T' If the character is part of the other permissions and the file is not executable or the directory is not searchable by others, and the 'sticky' (S_ISVTX) bit is set.

• 's' If the character is part of the owner permissions and the file is executable or the directory searchable by the owner, and the set-user-id bit is set.

• 's' If the character is part of the group permissions and the file is executable or the directory searchable by the group, and the set-group-id bit is set.

• 't' If the character is part of the other permissions and the file is executable or the directory searchable by others, and the ”sticky” (S_ISVTX) bit is set.

• 'x' The file is executable or the directory is searchable.

• '-' If none of the above apply. Most commonly the third character is either 'x' or -.

On Windows the permissions are displayed as a 3 character string where the third character is only - or x.

Examples

# Integer and numeric
fs_perms(420L)
fs_perms(c(511, 420))

# Octal
fs_perms("777")
fs_perms(c("777", "644"))

# Symbolic
fs_perms("a+rwx")
fs_perms(c("a+rwx", "u+rw,go+r"))

# Use the `&` and `|`operators to check for certain permissions
(fs_perms("777") & "u+r") == "u+r"