Pathname represents the name of a file or directory on the filesystem, but not the file itself.

The pathname depends on the Operating System: Unix, Windows, etc. This library works with pathnames of local OS, however non-Unix pathnames are supported experimentally.

A Pathname can be relative or absolute. It's not until you try to reference the file that it even matters whether the file exists or not.

Pathname is immutable. It has no method for destructive update.

The goal of this class is to manipulate file path information in a neater way than standard Ruby provides. The examples below demonstrate the difference.

All functionality from File, FileTest, and some from Dir and FileUtils is included, in an unsurprising way. It is essentially a facade for all of these, and more.

Examples

Example 1: Using

require 'pathname'
pn = Pathname.new("/usr/bin/ruby")
size = pn.size              # 27662
isdir = pn.directory?       # false
dir  = pn.dirname           # Pathname:/usr/bin
base = pn.basename          # Pathname:ruby
dir, base = pn.split        # [Pathname:/usr/bin, Pathname:ruby]
data = pn.read
pn.open { |f| _ }
pn.each_line { |line| _ }

Example 2: Using standard Ruby

pn = "/usr/bin/ruby"
size = File.size(pn)        # 27662
isdir = File.directory?(pn) # false
dir  = File.dirname(pn)     # "/usr/bin"
base = File.basename(pn)    # "ruby"
dir, base = File.split(pn)  # ["/usr/bin", "ruby"]
data = File.read(pn)
File.open(pn) { |f| _ }
File.foreach(pn) { |line| _ }

Example 3: Special features

p1 = Pathname.new("/usr/lib")   # Pathname:/usr/lib
p2 = p1 + "ruby/1.8"            # Pathname:/usr/lib/ruby/1.8
p3 = p1.parent                  # Pathname:/usr
p4 = p2.relative_path_from(p3)  # Pathname:lib/ruby/1.8
pwd = Pathname.pwd              # Pathname:/home/gavin
pwd.absolute?                   # true
p5 = Pathname.new "."           # Pathname:.
p5 = p5 + "music/../articles"   # Pathname:music/../articles
p5.cleanpath                    # Pathname:articles
p5.realpath                     # Pathname:/home/gavin/articles
p5.children                     # [Pathname:/home/gavin/articles/linux, ...]

Breakdown of functionality

Core methods

These methods are effectively manipulating a String, because that's all a path is. None of these access the file system except for mountpoint?, children, each_child, realdirpath and realpath.

These methods are a facade for FileTest:

These methods are a facade for File:

Directory methods

These methods are a facade for Dir:

These methods are a facade for IO:

Utilities

These methods are a mixture of Find, FileUtils, and others:

As the above section shows, most of the methods in Pathname are facades. The documentation for these methods generally just says, for instance, “See FileTest.writable?”, as you should be familiar with the original method anyway, and its documentation (e.g. through ri) will contain more information. In some cases, a brief description will follow.


+

Appends a pathname fragment to self to produce a new Pathname object.

p1 = Pathname.new("/usr")      # Pathname:/usr
p2 = p1 + "bin/ruby"           # Pathname:/usr/bin/ruby
p3 = p1 + "/etc/passwd"        # Pathname:/etc/passwd

# / is aliased to +.
p4 = p1 / "bin/ruby"           # Pathname:/usr/bin/ruby
p5 = p1 / "/etc/passwd"        # Pathname:/etc/passwd

This method doesn't access the file system; it is pure string manipulation.

/

No documentation available

<=>

Provides a case-sensitive comparison operator for pathnames.

Pathname.new('/usr') <=> Pathname.new('/usr/bin')
    #=> -1
Pathname.new('/usr/bin') <=> Pathname.new('/usr/bin')
    #=> 0
Pathname.new('/usr/bin') <=> Pathname.new('/USR/BIN')
    #=> 1

It will return -1, 0 or 1 depending on the value of the left argument relative to the right argument. Or it will return nil if the arguments are not comparable.

==

Compare this pathname with other. The comparison is string-based. Be aware that two different paths (foo.txt and ./foo.txt) can refer to the same file.

===

Compare this pathname with other. The comparison is string-based. Be aware that two different paths (foo.txt and ./foo.txt) can refer to the same file.

absolute?

Predicate method for testing whether a path is absolute.

It returns true if the pathname begins with a slash.

p = Pathname.new('/im/sure')
p.absolute?
    #=> true

p = Pathname.new('not/so/sure')
p.absolute?
    #=> false

ascend

Iterates over and yields a new Pathname object for each element in the given path in ascending order.

Pathname.new('/path/to/some/file.rb').ascend {|v| p v}
   #<Pathname:/path/to/some/file.rb>
   #<Pathname:/path/to/some>
   #<Pathname:/path/to>
   #<Pathname:/path>
   #<Pathname:/>

Pathname.new('path/to/some/file.rb').ascend {|v| p v}
   #<Pathname:path/to/some/file.rb>
   #<Pathname:path/to/some>
   #<Pathname:path/to>
   #<Pathname:path>

Returns an Enumerator if no block was given.

enum = Pathname.new("/usr/bin/ruby").ascend
  # ... do stuff ...
enum.each { |e| ... }
  # yields Pathnames /usr/bin/ruby, /usr/bin, /usr, and /.

It doesn't access the filesystem.

Returns the last access time for the file.

See File.atime.

basename

Returns the last component of the path.

See File.basename.

Returns all the bytes from the file, or the first N if specified.

See File.binread.

Returns the birth time for the file. If the platform doesn't have birthtime, raises NotImplementedError.

See File.birthtime.

blockdev?

chardev?

children

Returns the children of the directory (files and subdirectories, not recursive) as an array of Pathname objects.

By default, the returned pathnames will have enough information to access the files. If you set with_directory to false, then the returned pathnames will contain the filename only.

For example:

pn = Pathname("/usr/lib/ruby/1.8")
pn.children
    # -> [ Pathname:/usr/lib/ruby/1.8/English.rb,
           Pathname:/usr/lib/ruby/1.8/Env.rb,
           Pathname:/usr/lib/ruby/1.8/abbrev.rb, ... ]
pn.children(false)
    # -> [ Pathname:English.rb, Pathname:Env.rb, Pathname:abbrev.rb, ... ]

Note that the results never contain the entries . and .. in the directory because they are not children.

Changes file permissions.

See File.chmod.

Change owner and group of the file.

See File.chown.

cleanpath

Returns clean pathname of self with consecutive slashes and useless dots removed. The filesystem is not accessed.

If consider_symlink is true, then a more conservative algorithm is used to avoid breaking symbolic linkages. This may retain more .. entries than absolutely necessary, but without accessing the filesystem, this can't be avoided.

See Pathname#realpath.

Returns the last change time, using directory information, not the file itself.

See File.ctime.

delete

Removes a file or directory, using File.unlink if self is a file, or Dir.unlink as necessary.

descend

Iterates over and yields a new Pathname object for each element in the given path in descending order.

Pathname.new('/path/to/some/file.rb').descend {|v| p v}
   #<Pathname:/>
   #<Pathname:/path>
   #<Pathname:/path/to>
   #<Pathname:/path/to/some>
   #<Pathname:/path/to/some/file.rb>

Pathname.new('path/to/some/file.rb').descend {|v| p v}
   #<Pathname:path>
   #<Pathname:path/to>
   #<Pathname:path/to/some>
   #<Pathname:path/to/some/file.rb>

Returns an Enumerator if no block was given.

enum = Pathname.new("/usr/bin/ruby").descend
  # ... do stuff ...
enum.each { |e| ... }
  # yields Pathnames /, /usr, /usr/bin, and /usr/bin/ruby.

It doesn't access the filesystem.

directory?

dirname

Returns all but the last component of the path.

See File.dirname.

each_child

Iterates over the children of the directory (files and subdirectories, not recursive).

It yields Pathname object for each child.

By default, the yielded pathnames will have enough information to access the files.

If you set with_directory to false, then the returned pathnames will contain the filename only.

Pathname("/usr/local").each_child {|f| p f }
#=> #<Pathname:/usr/local/share>
#   #<Pathname:/usr/local/bin>
#   #<Pathname:/usr/local/games>
#   #<Pathname:/usr/local/lib>
#   #<Pathname:/usr/local/include>
#   #<Pathname:/usr/local/sbin>
#   #<Pathname:/usr/local/src>
#   #<Pathname:/usr/local/man>

Pathname("/usr/local").each_child(false) {|f| p f }
#=> #<Pathname:share>
#   #<Pathname:bin>
#   #<Pathname:games>
#   #<Pathname:lib>
#   #<Pathname:include>
#   #<Pathname:sbin>
#   #<Pathname:src>
#   #<Pathname:man>

Note that the results never contain the entries . and .. in the directory because they are not children.

See Pathname#children

each_entry

Iterates over the entries (files and subdirectories) in the directory, yielding a Pathname object for each entry.

each_filename

Iterates over each component of the path.

Pathname.new("/usr/bin/ruby").each_filename {|filename| ... }
  # yields "usr", "bin", and "ruby".

Returns an Enumerator if no block was given.

enum = Pathname.new("/usr/bin/ruby").each_filename
  # ... do stuff ...
enum.each { |e| ... }
  # yields "usr", "bin", and "ruby".

empty?

Tests the file is empty.

See Dir#empty? and FileTest.empty?.

entries

Return the entries (files and subdirectories) in the directory, each as a Pathname object.

The results contains just the names in the directory, without any trailing slashes or recursive look-up.

pp Pathname.new('/usr/local').entries
#=> [#<Pathname:share>,
#    #<Pathname:lib>,
#    #<Pathname:..>,
#    #<Pathname:include>,
#    #<Pathname:etc>,
#    #<Pathname:bin>,
#    #<Pathname:man>,
#    #<Pathname:games>,
#    #<Pathname:.>,
#    #<Pathname:sbin>,
#    #<Pathname:src>]

The result may contain the current directory #<Pathname:.> and the parent directory #<Pathname:..>.

If you don't want . and .. and want directories, consider Pathname#children.

eql?

Compare this pathname with other. The comparison is string-based. Be aware that two different paths (foo.txt and ./foo.txt) can refer to the same file.

executable?

executable_real?

exist?

expand_path

Returns the absolute path for the file.

See File.expand_path.

extname

Returns the file's extension.

See File.extname.

file?

find

Iterates over the directory tree in a depth first manner, yielding a Pathname for each file under “this” directory.

Returns an Enumerator if no block is given.

Since it is implemented by the standard library module Find, Find.prune can be used to control the traversal.

If self is ., yielded pathnames begin with a filename in the current directory, not ./.

See Find.find

Return true if the receiver matches the given pattern.

See File.fnmatch.

Returns “type” of file (“file”, “directory”, etc).

See File.ftype.

getwd

Returns the current working directory as a Pathname.

Pathname.getwd
    #=> #<Pathname:/home/zzak/projects/ruby>

See Dir.getwd.

glob

Returns or yields Pathname objects.

Pathname.glob("lib/i*.rb")
    #=> [#<Pathname:lib/ipaddr.rb>, #<Pathname:lib/irb.rb>]

See Dir.glob.

grpowned?

join

Joins the given pathnames onto self to create a new Pathname object.

path0 = Pathname.new("/usr")                # Pathname:/usr
path0 = path0.join("bin/ruby")              # Pathname:/usr/bin/ruby
    # is the same as
path1 = Pathname.new("/usr") + "bin/ruby"   # Pathname:/usr/bin/ruby
path0 == path1
    #=> true

Same as Pathname.chmod, but does not follow symbolic links.

See File.lchmod.

Same as Pathname.chown, but does not follow symbolic links.

See File.lchown.

lstat

See File.lstat.

Creates a hard link at pathname.

See File.link.

Creates a symbolic link.

See File.symlink.

mkdir

Create the referenced directory.

See Dir.mkdir.

mkpath

Creates a full path, including any intermediate directories that don't yet exist.

See FileUtils.mkpath and FileUtils.mkdir_p

mountpoint?

Returns true if self points to a mountpoint.

Returns the last modified time of the file.

See File.mtime.

new

Create a Pathname object from the given String (or String-like object). If path contains a NULL character (\0), an ArgumentError is raised.

open

Opens the file for reading or writing.

See File.open.

opendir

Opens the referenced directory.

See Dir.open.

owned?

parent

Returns the parent directory.

This is same as self + '..'.

pipe?

pwd

Returns the current working directory as a Pathname.

Pathname.getwd
    #=> #<Pathname:/home/zzak/projects/ruby>

See Dir.getwd.

Returns all data from the file, or the first N bytes if specified.

See File.read.

readable?

readable_real?

readlink

Read symbolic link.

See File.readlink.

realdirpath

Returns the real (absolute) pathname of self in the actual filesystem.

Does not contain symlinks or useless dots, .. and ..

The last component of the real pathname can be nonexistent.

realpath

Returns the real (absolute) pathname for self in the actual filesystem.

Does not contain symlinks or useless dots, .. and ..

All components of the pathname must exist when this method is called.

relative?

The opposite of Pathname#absolute?

It returns false if the pathname begins with a slash.

p = Pathname.new('/im/sure')
p.relative?
    #=> false

p = Pathname.new('not/so/sure')
p.relative?
    #=> true

relative_path_from

Returns a relative path from the given base_directory to the receiver.

If self is absolute, then base_directory must be absolute too.

If self is relative, then base_directory must be relative too.

This method doesn't access the filesystem. It assumes no symlinks.

ArgumentError is raised when it cannot find a relative path.

rename

Rename the file.

See File.rename.

rmdir

Remove the referenced directory.

See Dir.rmdir.

rmtree

Recursively deletes a directory, including all directories beneath it.

See FileUtils.rm_r

root?

Predicate method for root directories. Returns true if the pathname consists of consecutive slashes.

It doesn't access the filesystem. So it may return false for some pathnames which points to roots such as /usr/...

setgid?

setuid?

size

size?

socket?

split

Returns the dirname and the basename in an Array.

See File.split.

stat

Returns a File::Stat object.

See File.stat.

sticky?

sub

Return a pathname which is substituted by String#sub.

path1 = Pathname.new('/usr/bin/perl')
path1.sub('perl', 'ruby')
    #=> #<Pathname:/usr/bin/ruby>

sub_ext

Return a pathname with repl added as a suffix to the basename.

If self has no extension part, repl is appended.

Pathname.new('/usr/bin/shutdown').sub_ext('.rb')
    #=> #<Pathname:/usr/bin/shutdown.rb>

symlink?

Returns pathname. This method is deprecated and will be removed in Ruby 3.2.

Return the path as a String.

to_path is implemented so Pathname objects are usable with File.open, etc.

Return the path as a String.

to_path is implemented so Pathname objects are usable with File.open, etc.

truncate

Truncates the file to length bytes.

See File.truncate.

unlink

Removes a file or directory, using File.unlink if self is a file, or Dir.unlink as necessary.

Returns pathname. This method is deprecated and will be removed in Ruby 3.2.

utime

Update the access and modification times of the file.

See File.utime.

world_readable?

world_writable?

writable?

writable_real?

zero?