Same as File::stat
, but does not follow the last symbolic link. Instead, reports on the link itself.
File.symlink("testfile", "link2test") #=> 0 File.stat("testfile").size #=> 66 File.lstat("link2test").size #=> 8 File.stat("link2test").size #=> 66
Creates a new name for an existing file using a hard link. Will not overwrite new_name if it already exists (raising a subclass of SystemCallError
). Not available on all platforms.
File.link("testfile", ".testfile") #=> 0 IO.readlines(".testfile")[0] #=> "This is line one\n"
Creates a symbolic link called new_name for the existing file old_name. Raises a NotImplemented
exception on platforms that do not support symbolic links.
File.symlink("testfile", "link2test") #=> 0
Returns the name of the file referenced by the given link. Not available on all platforms.
File.symlink("testfile", "link2test") #=> 0 File.readlink("link2test") #=> "testfile"
Deletes the named files, returning the number of names passed as arguments. Raises an exception on any error. See also Dir::rmdir
.
Truncates the file file_name to be at most integer bytes long. Not available on all platforms.
f = File.new("out", "w") f.write("1234567890") #=> 10 f.close #=> nil File.truncate("out", 5) #=> 0 File.size("out") #=> 5
Returns a new string formed by joining the strings using File::SEPARATOR
.
File.join("usr", "mail", "gumby") #=> "usr/mail/gumby"
Same as IO#stat
, but does not follow the last symbolic link. Instead, reports on the link itself.
File.symlink("testfile", "link2test") #=> 0 File.stat("testfile").size #=> 66 f = File.new("link2test") f.lstat.size #=> 8 f.stat.size #=> 66
Truncates file to at most integer bytes. The file must be opened for writing. Not available on all platforms.
f = File.new("out", "w") f.syswrite("1234567890") #=> 10 f.truncate(5) #=> 0 f.close() #=> nil File.size("out") #=> 5
Return true
if the named file exists.
file_name can be an IO
object.
“file exists” means that stat() or fstat() system call is successful.
Deprecated method. Don’t use.
Returns true
if the named file is writable by the effective user and group id of this process. See eaccess(3).
Returns true
if the named file is a symbolic link.
Returns true
if the named file has the sticky bit set.
Returns a string which represents the encoding for programmers.
Encoding::UTF_8.inspect #=> "#<Encoding:UTF-8>" Encoding::ISO_2022_JP.inspect #=> "#<Encoding:ISO-2022-JP (dummy)>"
Returns the list of loaded encodings.
Encoding.list #=> [#<Encoding:ASCII-8BIT>, #<Encoding:UTF-8>, #<Encoding:ISO-2022-JP (dummy)>] Encoding.find("US-ASCII") #=> #<Encoding:US-ASCII> Encoding.list #=> [#<Encoding:ASCII-8BIT>, #<Encoding:UTF-8>, #<Encoding:US-ASCII>, #<Encoding:ISO-2022-JP (dummy)>]
Search the encoding with specified name. name should be a string.
Encoding.find("US-ASCII") #=> #<Encoding:US-ASCII>
Names which this method accept are encoding names and aliases including following special aliases
default external encoding
default internal encoding
locale encoding
filesystem encoding
An ArgumentError
is raised when no encoding with name. Only Encoding.find("internal")
however returns nil when no encoding named “internal”, in other words, when Ruby has no default internal encoding.
Rewinds the enumeration sequence to the beginning.
If the enclosed object responds to a “rewind” method, it is called.
Creates a printable version of e.
Returns a Digest
subclass by name
in a thread-safe manner even when on-demand loading is involved.
require 'digest' Digest("MD5") # => Digest::MD5 Digest(:SHA256) # => Digest::SHA256 Digest(:Foo) # => LoadError: library not found for class Digest::Foo -- digest/foo
Mark the object as tainted.
Objects that are marked as tainted will be restricted from various built-in methods. This is to prevent insecure data, such as command-line arguments or strings read from Kernel#gets
, from inadvertently compromising the user’s system.
To check whether an object is tainted, use tainted?
.
You should only untaint a tainted object if your code has inspected it and determined that it is safe. To do so use untaint
.
Returns a string containing a human-readable representation of obj. The default inspect
shows the object’s class name, an encoding of the object id, and a list of the instance variables and their values (by calling inspect
on each of them). User defined classes should override this method to provide a better representation of obj. When overriding this method, it should return a string whose encoding is compatible with the default external encoding.
[ 1, 2, 3..4, 'five' ].inspect #=> "[1, 2, 3..4, \"five\"]" Time.new.inspect #=> "2008-03-08 19:43:39 +0900" class Foo end Foo.new.inspect #=> "#<Foo:0x0300c868>" class Bar def initialize @bar = 1 end end Bar.new.inspect #=> "#<Bar:0x0300c868 @bar=1>"
Return this exception’s class name and message