6.28. Ruby File classes and methods

File represents a connection to a normal file stdio object. open returns an instance of this class for a normal file.

6.28.1. Class method #

Serial number	Method and description
1	`File::atime( path)` returns the last access time of the path.
2	`File::basename( path[, suffix])` Returns the file name at the end of the path. If suffix is specified, it is removed from the end of the file name. For example: File.basename (”/ home/users/bin/ruby.exe”) # = > “ruby.exe”
3	`File::blockdev?( path` returns true if path is a block device.
4	`File::chardev?( path)` returns true if path is a character device.
5	`File::chmod( mode, path...)` changes the permission mode of the specifiedfile.
6	`File::chown( owner, group, path...)` changes the owner and group of the specified file.
7	`File::ctime( path)` returns the last inode change time of the path.
8	`File::delete( path...)` `File::unlink( path...)` deletes the specified file.
9	`File::directory?( path)` if path is a directory, true is returned.
10	`File::dirname( path)` returns the directory portion of the path, excluding the last file name.
11	`File::executable?( path)` returns true if path is executable.
12	`File::executable_real?( path)` if path is executable with true user rights, it returns true.
13	`File::exist?( path)` returns true if path exists.
14	`File::expand_path( path[, dir])` return the absolute path of path, extend~ to the home directory of the process owner, and ~ user to the home directory of the user. The relative path is relative to the directory specified by dir, or to the current working directory if dir is omitted.
15	`File::file?( path)` if path is a normal file, true is returned.
16	`File::ftype( path)` returns one of the following strings, indicating the file type: file-normal file directory-directory characterSpecial-character special file blockSpecial-block special file fifo-named pipe (FIFO) link-symbolic link socket-Socket unknown-unknown file type
17	`File::grpowned?( path)` returns true if path is owned by the group to which the user belongs.
18	`File::join( item...)` returns a string concatenated by the specified items and uses the `File::Separator` to separate. For example: File::join (“”, “home”, “usrs”, “bin”) # = > “/ home/usrs/bin”
19	`File::link( old, new)` create a hard link to the file old.
20	`File::lstat( path)` is the same as stat, but it returns information on its own symbolic link, not the file it points to.
21	`File::mtime( path)` returns the time when the path was last modified.
22	`File::new( path[, mode="r"])` `File::open( path[, mode="r"])` `File::open( path[, mode="r"]) {\|f\| ...}` Open the file. If a block is specified, the block is executed by passing a new file as a parameter. When the block exits, the file closes automatically. These methods are different from Kernel.open in that even if path starts with \| , subsequent strings are not run as commands.
23	`File::owned?( path)` returns true if path is owned by a valid user.
24	`File::pipe?( path)` returns true if path is a pipe.
25	`File::readable?( path)` returns true if path is readable.
26	`File::readable_real?( path)` if path is readable through true user rights, it returns true.
27	`File::readlink( path)` returns the file that path points to.
28	`File::rename( old, new)` change the file name old to new.
29	`File::setgid?( path)` if the set-group-id permission bit of path is set, true is returned.
30	`File::setuid?( path)` if the set-user-id permission bit of path is set, true is returned.
31	`File::size( path)` Returns the file size of the path.
32	`File::size?( path)` Returns the file size of path, or nil if 0.
33	`File::socket?( path)` Returns true if path is a socket.
34	`File::split( path)` Returns an array containing the contents of path, andthe path is divided into `File::dirname(path)` and `File::basename(path)` .
35	`File::stat( path)` object with information on the path `File::Stat` object.
36	`File::sticky?( path)` Returns true if the sticky bit of path is set.
37	`File::symlink( old, new)` Create a symbolic link to the file old.
38	`File::symlink?( path)` Returns true if path is a symbolic link.
39	`File::truncate( path, len)` Truncate the specified file as len bytes.
40	`File::unlink( path...)` Deletes the file given by path.
41	`File::umask([ mask])` If no parameter is specified, the current umask is returned for the process. If a parameter is specified, umask is set and the old umask is returned.
42	`File::utime( atime, mtime, path...)` Changes the access and modification time of the specified file.
43	`File::writable?( path)` Returns true if path is writable.
44	`File::writable_real?( path)` If path is writable with true user rights, true is returned.
45	`File::zero?( path)` Returns true if the file size of path is 0.

6.28.2. Example method #

Assuming f is an instance of the `` File` class:

Serial number	Method and description
1	F.atime returns the last access time of f.
2	`f.chmode( mode)` Change the permission mode of f.
3	`f.chown( owner, group)` Change the owner and group of f.
4	F.ctime returns the last inode change time of f.
5	F.flock (op) calls flock (2). Op can be 0 or a logical value or File class constants LOCK_EX, LOCK_NB, LOCK_SH, and LOCK_UN.
6	F.lstat is the same as stat, but it returns information on its own symbolic link, not the file it points to.
7	F.mtime returns the last modification time of f.
8	F.path returns the pathname used to create f.
9	`f.reopen( path[, mode="r"])` Reopen the file.
10	`f.truncate( len)` Truncate f to len bytes.