Module

fileutils.rb

Copyright © 2000-2007 Minero Aoki

This program is free software. You can distribute/modify this program under the same terms of ruby.

module FileUtils

Namespace for several file utility methods for copying, moving, removing, etc.

Module Functions

require 'fileutils'

FileUtils.cd(dir, options)
FileUtils.cd(dir, options) {|dir| .... }
FileUtils.pwd()
FileUtils.mkdir(dir, options)
FileUtils.mkdir(list, options)
FileUtils.mkdir_p(dir, options)
FileUtils.mkdir_p(list, options)
FileUtils.rmdir(dir, options)
FileUtils.rmdir(list, options)
FileUtils.ln(old, new, options)
FileUtils.ln(list, destdir, options)
FileUtils.ln_s(old, new, options)
FileUtils.ln_s(list, destdir, options)
FileUtils.ln_sf(src, dest, options)
FileUtils.cp(src, dest, options)
FileUtils.cp(list, dir, options)
FileUtils.cp_r(src, dest, options)
FileUtils.cp_r(list, dir, options)
FileUtils.mv(src, dest, options)
FileUtils.mv(list, dir, options)
FileUtils.rm(list, options)
FileUtils.rm_r(list, options)
FileUtils.rm_rf(list, options)
FileUtils.install(src, dest, mode = <src's>, options)
FileUtils.chmod(mode, list, options)
FileUtils.chmod_R(mode, list, options)
FileUtils.chown(user, group, list, options)
FileUtils.chown_R(user, group, list, options)
FileUtils.touch(list, options)

The options parameter is a hash of options, taken from the list :force, :noop, :preserve, and :verbose. :noop means that no changes are made. The other two are obvious. Each method documents the options that it honours.

All methods that have the concept of a “source” file or directory can take either one file or a list of files in that argument. See the method documentation for examples.

There are some `low level' methods, which do not accept any option:

FileUtils.copy_entry(src, dest, preserve = false, dereference = false)
FileUtils.copy_file(src, dest, preserve = false, dereference = true)
FileUtils.copy_stream(srcstream, deststream)
FileUtils.remove_entry(path, force = false)
FileUtils.remove_entry_secure(path, force = false)
FileUtils.remove_file(path, force = false)
FileUtils.compare_file(path_a, path_b)
FileUtils.compare_stream(stream_a, stream_b)
FileUtils.uptodate?(file, cmp_list)

module FileUtils::Verbose

This module has all methods of FileUtils module, but it outputs messages before acting. This equates to passing the :verbose flag to methods in FileUtils.

module FileUtils::NoWrite

This module has all methods of FileUtils module, but never changes files/directories. This equates to passing the :noop flag to methods in FileUtils.

module FileUtils::DryRun

This module has all methods of FileUtils module, but never changes files/directories. This equates to passing the :noop and :verbose flags to methods in FileUtils.

Constants
No documentation available
No documentation available

This hash table holds command options.

Class Methods

Options: verbose

Changes the current directory to the directory dir.

If this method is called with block, resumes to the old working directory after the block execution finished.

FileUtils.cd('/', :verbose => true)   # chdir and report it

FileUtils.cd('/') do  # chdir
  [...]               # do something
end                   # return to original directory
An alias for cd

Options: noop verbose

Changes permission bits on the named files (in list) to the bit pattern represented by mode.

mode is the symbolic and absolute mode can be used.

Absolute mode is

FileUtils.chmod 0755, 'somecommand'
FileUtils.chmod 0644, %w(my.rb your.rb his.rb her.rb)
FileUtils.chmod 0755, '/usr/bin/ruby', :verbose => true

Symbolic mode is

FileUtils.chmod "u=wrx,go=rx", 'somecommand'
FileUtils.chmod "u=wr,go=rr", %w(my.rb your.rb his.rb her.rb)
FileUtils.chmod "u=wrx,go=rx", '/usr/bin/ruby', :verbose => true
“a”

is user, group, other mask.

“u”

is user's mask.

“g”

is group's mask.

“o”

is other's mask.

“w”

is write permission.

“r”

is read permission.

“x”

is execute permission.

“X”

is execute permission for directories only, must be used in conjunction with “+”

“s”

is uid, gid.

“t”

is sticky bit.

“+”

is added to a class given the specified mode.

“-”

Is removed from a given class given mode.

“=”

Is the exact nature of the class will be given a specified mode.

Options: noop verbose force

Changes permission bits on the named files (in list) to the bit pattern represented by mode.

FileUtils.chmod_R 0700, "/tmp/app.#{$$}"
FileUtils.chmod_R "u=wrx", "/tmp/app.#{$$}"

Options: noop verbose

Changes owner and group on the named files (in list) to the user user and the group group. user and group may be an ID (Integer/String) or a name (String). If user or group is nil, this method does not change the attribute.

FileUtils.chown 'root', 'staff', '/usr/local/bin/ruby'
FileUtils.chown nil, 'bin', Dir.glob('/usr/bin/*'), :verbose => true

Options: noop verbose force

Changes owner and group on the named files (in list) to the user user and the group group recursively. user and group may be an ID (Integer/String) or a name (String). If user or group is nil, this method does not change the attribute.

FileUtils.chown_R 'www', 'www', '/var/www/htdocs'
FileUtils.chown_R 'cvs', 'cvs', '/var/cvs', :verbose => true
An alias for compare_file

Returns an Array of method names which have the option opt.

p FileUtils.collect_method(:preserve) #=> ["cp", "cp_r", "copy", "install"]

Returns an Array of method names which have any options.

p FileUtils.commands  #=> ["chmod", "cp", "cp_r", "install", ...]

Returns true if the contents of a file A and a file B are identical.

FileUtils.compare_file('somefile', 'somefile')  #=> true
FileUtils.compare_file('/bin/cp', '/bin/mv')    #=> maybe false

Returns true if the contents of a stream a and b are identical.

An alias for cp

Copies a file system entry src to dest. If src is a directory, this method copies its contents recursively. This method preserves file types, c.f. symlink, directory… (FIFO, device files and etc. are not supported yet)

Both of src and dest must be a path name. src must exist, dest must not exist.

If preserve is true, this method preserves owner, group, and modified time. Permissions are copied regardless preserve.

If dereference_root is true, this method dereference tree root.

If remove_destination is true, this method removes each destination file before copy.

Copies file contents of src to dest. Both of src and dest must be a path name.

Copies stream src to dest. src must respond to read(n) and dest must respond to write(str).

Options: preserve noop verbose

Copies a file content src to dest. If dest is a directory, copies src to dest/src.

If src is a list of files, then dest must be a directory.

FileUtils.cp 'eval.c', 'eval.c.org'
FileUtils.cp %w(cgi.rb complex.rb date.rb), '/usr/lib/ruby/1.6'
FileUtils.cp %w(cgi.rb complex.rb date.rb), '/usr/lib/ruby/1.6', :verbose => true
FileUtils.cp 'symlink', 'dest'   # copy content, "dest" is not a symlink

Options: preserve noop verbose dereference_root remove_destination

Copies src to dest. If src is a directory, this method copies all its contents recursively. If dest is a directory, copies src to dest/src.

src can be a list of files.

# Installing Ruby library "mylib" under the site_ruby
FileUtils.rm_r site_ruby + '/mylib', :force
FileUtils.cp_r 'lib/', site_ruby + '/mylib'

# Examples of copying several files to target directory.
FileUtils.cp_r %w(mail.rb field.rb debug/), site_ruby + '/tmail'
FileUtils.cp_r Dir.glob('*.rb'), '/home/aamine/lib/ruby', :noop => true, :verbose => true

# If you want to copy all contents of a directory instead of the
# directory itself, c.f. src/x -> dest/x, src/y -> dest/y,
# use following code.
FileUtils.cp_r 'src/.', 'dest'     # cp_r('src', 'dest') makes dest/src,
                                   # but this doesn't.
An alias for pwd

Returns true if the method mid have an option opt.

p FileUtils.have_option?(:cp, :noop)     #=> true
p FileUtils.have_option?(:rm, :force)    #=> true
p FileUtils.have_option?(:rm, :preserve) #=> false
An alias for compare_file

Options: mode preserve noop verbose

If src is not same as dest, copies it and changes the permission mode to mode. If dest is a directory, destination is dest/src. This method removes destination before copy.

FileUtils.install 'ruby', '/usr/local/bin/ruby', :mode => 0755, :verbose => true
FileUtils.install 'lib.rb', '/usr/local/lib/ruby/site_ruby', :verbose => true
An alias for ln

Options: force noop verbose

ln(old, new, options = {})

Creates a hard link new which points to old. If new already exists and it is a directory, creates a link new/old. If new already exists and it is not a directory, raises Errno::EEXIST. But if :force option is set, overwrite new.

FileUtils.ln 'gcc', 'cc', :verbose => true
FileUtils.ln '/usr/bin/emacs21', '/usr/bin/emacs'

ln(list, destdir, options = {})

Creates several hard links in a directory, with each one pointing to the item in list. If destdir is not a directory, raises Errno::ENOTDIR.

include FileUtils
cd '/sbin'
FileUtils.ln %w(cp mv mkdir), '/bin'   # Now /sbin/cp and /bin/cp are linked.

Options: force noop verbose

ln_s(old, new, options = {})

Creates a symbolic link new which points to old. If new already exists and it is a directory, creates a symbolic link new/old. If new already exists and it is not a directory, raises Errno::EEXIST. But if :force option is set, overwrite new.

FileUtils.ln_s '/usr/bin/ruby', '/usr/local/bin/ruby'
FileUtils.ln_s 'verylongsourcefilename.c', 'c', :force => true

ln_s(list, destdir, options = {})

Creates several symbolic links in a directory, with each one pointing to the item in list. If destdir is not a directory, raises Errno::ENOTDIR.

If destdir is not a directory, raises Errno::ENOTDIR.

FileUtils.ln_s Dir.glob('bin/*.rb'), '/home/aamine/bin'

Options: noop verbose

Same as

#ln_s(src, dest, :force => true)

Options: mode noop verbose

Creates one or more directories.

FileUtils.mkdir 'test'
FileUtils.mkdir %w( tmp data )
FileUtils.mkdir 'notexist', :noop => true  # Does not really create.
FileUtils.mkdir 'tmp', :mode => 0700

Options: mode noop verbose

Creates a directory and all its parent directories. For example,

FileUtils.mkdir_p '/usr/local/lib/ruby'

causes to make following directories, if it does not exist.

* /usr
* /usr/local
* /usr/local/lib
* /usr/local/lib/ruby

You can pass several directories at a time in a list.

An alias for mv

Options: force noop verbose

Moves file(s) src to dest. If file and dest exist on the different disk partition, the file is copied then the original file is removed.

FileUtils.mv 'badname.rb', 'goodname.rb'
FileUtils.mv 'stuff.rb', '/notexist/lib/ruby', :force => true  # no error

FileUtils.mv %w(junk.txt dust.txt), '/home/aamine/.trash/'
FileUtils.mv Dir.glob('test*.rb'), 'test', :noop => true, :verbose => true

Returns an Array of option names.

p FileUtils.options  #=> ["noop", "force", "verbose", "preserve", "mode"]

Returns an Array of option names of the method mid.

p FileUtils.options_of(:rm)  #=> ["noop", "verbose", "force"]
::

Options: (none)

Returns the name of the current directory.

An alias for rm

Removes a directory dir and its contents recursively. This method ignores StandardError if force is true.

This method removes a file system entry path. path might be a regular file, a directory, or something. If path is a directory, remove it recursively.

See also remove_entry_secure.

This method removes a file system entry path. path shall be a regular file, a directory, or something. If path is a directory, remove it recursively. This method is required to avoid TOCTTOU (time-of-check-to-time-of-use) local security vulnerability of rm_r. rm_r causes security hole when:

* Parent directory is world writable (including /tmp).
* Removing directory tree includes world writable directory.
* The system has symbolic link.

To avoid this security hole, this method applies special preprocess. If path is a directory, this method chown(2) and chmod(2) all removing directories. This requires the current process is the owner of the removing whole directory tree, or is the super user (root).

WARNING: You must ensure that ALL parent directories cannot be moved by other untrusted users. For example, parent directories should not be owned by untrusted users, and should not be world writable except when the sticky bit set.

WARNING: Only the owner of the removing directory tree, or Unix super user (root) should invoke this method. Otherwise this method does not work.

For details of this security vulnerability, see Perl's case:

http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2005-0448
http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2004-0452

For fileutils.rb, this vulnerability is reported in [ruby-dev:26100].

Removes a file path. This method ignores StandardError if force is true.

Options: force noop verbose

Remove file(s) specified in list. This method cannot remove directories. All StandardErrors are ignored when the :force option is set.

FileUtils.rm %w( junk.txt dust.txt )
FileUtils.rm Dir.glob('*.so')
FileUtils.rm 'NotExistFile', :force => true   # never raises exception

Options: noop verbose

Equivalent to

#rm(list, :force => true)

Options: force noop verbose secure

remove files list[0] list[1]… If list[n] is a directory, removes its all contents recursively. This method ignores StandardError when :force option is set.

FileUtils.rm_r Dir.glob('/tmp/*')
FileUtils.rm_r '/', :force => true          #  :-)

WARNING: This method causes local vulnerability if one of parent directories or removing directory tree are world writable (including /tmp, whose permission is 1777), and the current process has strong privilege such as Unix super user (root), and the system has symbolic link. For secure removing, read the documentation of remove_entry_secure carefully, and set :secure option to true. Default is :secure=>false.

NOTE: This method calls remove_entry_secure if :secure option is set. See also remove_entry_secure.

Options: noop verbose secure

Equivalent to

#rm_r(list, :force => true)

WARNING: This method causes local vulnerability. Read the documentation of rm_r first.

Options: parents, noop, verbose

Removes one or more directories.

FileUtils.rmdir 'somedir'
FileUtils.rmdir %w(somedir anydir otherdir)
# Does not really remove directory; outputs message.
FileUtils.rmdir 'somedir', :verbose => true, :noop => true
An alias for rm_rf

Options: noop verbose mtime nocreate

Updates modification time (mtime) and access time (atime) of file(s) in list. Files are created if they don't exist.

FileUtils.touch 'timestamp'
FileUtils.touch Dir.glob('*.c');  system 'make'

Options: (none)

Returns true if new is newer than all old_list. Non-existent files are older than any file.

FileUtils.uptodate?('hello.o', %w(hello.c hello.h)) or \
    system 'make hello.o'
Instance Methods
No documentation available

Options: verbose

Changes the current directory to the directory dir.

If this method is called with block, resumes to the old working directory after the block execution finished.

FileUtils.cd('/', :verbose => true)   # chdir and report it

FileUtils.cd('/') do  # chdir
  [...]               # do something
end                   # return to original directory
An alias for cd

Options: noop verbose

Changes permission bits on the named files (in list) to the bit pattern represented by mode.

mode is the symbolic and absolute mode can be used.

Absolute mode is

FileUtils.chmod 0755, 'somecommand'
FileUtils.chmod 0644, %w(my.rb your.rb his.rb her.rb)
FileUtils.chmod 0755, '/usr/bin/ruby', :verbose => true

Symbolic mode is

FileUtils.chmod "u=wrx,go=rx", 'somecommand'
FileUtils.chmod "u=wr,go=rr", %w(my.rb your.rb his.rb her.rb)
FileUtils.chmod "u=wrx,go=rx", '/usr/bin/ruby', :verbose => true
“a”

is user, group, other mask.

“u”

is user's mask.

“g”

is group's mask.

“o”

is other's mask.

“w”

is write permission.

“r”

is read permission.

“x”

is execute permission.

“X”

is execute permission for directories only, must be used in conjunction with “+”

“s”

is uid, gid.

“t”

is sticky bit.

“+”

is added to a class given the specified mode.

“-”

Is removed from a given class given mode.

“=”

Is the exact nature of the class will be given a specified mode.

Options: noop verbose force

Changes permission bits on the named files (in list) to the bit pattern represented by mode.

FileUtils.chmod_R 0700, "/tmp/app.#{$$}"
FileUtils.chmod_R "u=wrx", "/tmp/app.#{$$}"

Options: noop verbose

Changes owner and group on the named files (in list) to the user user and the group group. user and group may be an ID (Integer/String) or a name (String). If user or group is nil, this method does not change the attribute.

FileUtils.chown 'root', 'staff', '/usr/local/bin/ruby'
FileUtils.chown nil, 'bin', Dir.glob('/usr/bin/*'), :verbose => true

Options: noop verbose force

Changes owner and group on the named files (in list) to the user user and the group group recursively. user and group may be an ID (Integer/String) or a name (String). If user or group is nil, this method does not change the attribute.

FileUtils.chown_R 'www', 'www', '/var/www/htdocs'
FileUtils.chown_R 'cvs', 'cvs', '/var/cvs', :verbose => true
An alias for compare_file

Returns true if the contents of a file A and a file B are identical.

FileUtils.compare_file('somefile', 'somefile')  #=> true
FileUtils.compare_file('/bin/cp', '/bin/mv')    #=> maybe false

Returns true if the contents of a stream a and b are identical.

An alias for cp

Copies a file system entry src to dest. If src is a directory, this method copies its contents recursively. This method preserves file types, c.f. symlink, directory… (FIFO, device files and etc. are not supported yet)

Both of src and dest must be a path name. src must exist, dest must not exist.

If preserve is true, this method preserves owner, group, and modified time. Permissions are copied regardless preserve.

If dereference_root is true, this method dereference tree root.

If remove_destination is true, this method removes each destination file before copy.

Copies file contents of src to dest. Both of src and dest must be a path name.

Copies stream src to dest. src must respond to read(n) and dest must respond to write(str).

Options: preserve noop verbose

Copies a file content src to dest. If dest is a directory, copies src to dest/src.

If src is a list of files, then dest must be a directory.

FileUtils.cp 'eval.c', 'eval.c.org'
FileUtils.cp %w(cgi.rb complex.rb date.rb), '/usr/lib/ruby/1.6'
FileUtils.cp %w(cgi.rb complex.rb date.rb), '/usr/lib/ruby/1.6', :verbose => true
FileUtils.cp 'symlink', 'dest'   # copy content, "dest" is not a symlink

Options: preserve noop verbose dereference_root remove_destination

Copies src to dest. If src is a directory, this method copies all its contents recursively. If dest is a directory, copies src to dest/src.

src can be a list of files.

# Installing Ruby library "mylib" under the site_ruby
FileUtils.rm_r site_ruby + '/mylib', :force
FileUtils.cp_r 'lib/', site_ruby + '/mylib'

# Examples of copying several files to target directory.
FileUtils.cp_r %w(mail.rb field.rb debug/), site_ruby + '/tmail'
FileUtils.cp_r Dir.glob('*.rb'), '/home/aamine/lib/ruby', :noop => true, :verbose => true

# If you want to copy all contents of a directory instead of the
# directory itself, c.f. src/x -> dest/x, src/y -> dest/y,
# use following code.
FileUtils.cp_r 'src/.', 'dest'     # cp_r('src', 'dest') makes dest/src,
                                   # but this doesn't.
An alias for pwd
An alias for compare_file

Options: mode preserve noop verbose

If src is not same as dest, copies it and changes the permission mode to mode. If dest is a directory, destination is dest/src. This method removes destination before copy.

FileUtils.install 'ruby', '/usr/local/bin/ruby', :mode => 0755, :verbose => true
FileUtils.install 'lib.rb', '/usr/local/lib/ruby/site_ruby', :verbose => true
An alias for ln

Options: force noop verbose

ln(old, new, options = {})

Creates a hard link new which points to old. If new already exists and it is a directory, creates a link new/old. If new already exists and it is not a directory, raises Errno::EEXIST. But if :force option is set, overwrite new.

FileUtils.ln 'gcc', 'cc', :verbose => true
FileUtils.ln '/usr/bin/emacs21', '/usr/bin/emacs'

ln(list, destdir, options = {})

Creates several hard links in a directory, with each one pointing to the item in list. If destdir is not a directory, raises Errno::ENOTDIR.

include FileUtils
cd '/sbin'
FileUtils.ln %w(cp mv mkdir), '/bin'   # Now /sbin/cp and /bin/cp are linked.

Options: force noop verbose

ln_s(old, new, options = {})

Creates a symbolic link new which points to old. If new already exists and it is a directory, creates a symbolic link new/old. If new already exists and it is not a directory, raises Errno::EEXIST. But if :force option is set, overwrite new.

FileUtils.ln_s '/usr/bin/ruby', '/usr/local/bin/ruby'
FileUtils.ln_s 'verylongsourcefilename.c', 'c', :force => true

ln_s(list, destdir, options = {})

Creates several symbolic links in a directory, with each one pointing to the item in list. If destdir is not a directory, raises Errno::ENOTDIR.

If destdir is not a directory, raises Errno::ENOTDIR.

FileUtils.ln_s Dir.glob('bin/*.rb'), '/home/aamine/bin'

Options: noop verbose

Same as

#ln_s(src, dest, :force => true)

Options: mode noop verbose

Creates one or more directories.

FileUtils.mkdir 'test'
FileUtils.mkdir %w( tmp data )
FileUtils.mkdir 'notexist', :noop => true  # Does not really create.
FileUtils.mkdir 'tmp', :mode => 0700

Options: mode noop verbose

Creates a directory and all its parent directories. For example,

FileUtils.mkdir_p '/usr/local/lib/ruby'

causes to make following directories, if it does not exist.

* /usr
* /usr/local
* /usr/local/lib
* /usr/local/lib/ruby

You can pass several directories at a time in a list.

An alias for mv

Options: force noop verbose

Moves file(s) src to dest. If file and dest exist on the different disk partition, the file is copied then the original file is removed.

FileUtils.mv 'badname.rb', 'goodname.rb'
FileUtils.mv 'stuff.rb', '/notexist/lib/ruby', :force => true  # no error

FileUtils.mv %w(junk.txt dust.txt), '/home/aamine/.trash/'
FileUtils.mv Dir.glob('test*.rb'), 'test', :noop => true, :verbose => true

Options: (none)

Returns the name of the current directory.

An alias for rm

Removes a directory dir and its contents recursively. This method ignores StandardError if force is true.

This method removes a file system entry path. path might be a regular file, a directory, or something. If path is a directory, remove it recursively.

See also remove_entry_secure.

This method removes a file system entry path. path shall be a regular file, a directory, or something. If path is a directory, remove it recursively. This method is required to avoid TOCTTOU (time-of-check-to-time-of-use) local security vulnerability of rm_r. rm_r causes security hole when:

* Parent directory is world writable (including /tmp).
* Removing directory tree includes world writable directory.
* The system has symbolic link.

To avoid this security hole, this method applies special preprocess. If path is a directory, this method chown(2) and chmod(2) all removing directories. This requires the current process is the owner of the removing whole directory tree, or is the super user (root).

WARNING: You must ensure that ALL parent directories cannot be moved by other untrusted users. For example, parent directories should not be owned by untrusted users, and should not be world writable except when the sticky bit set.

WARNING: Only the owner of the removing directory tree, or Unix super user (root) should invoke this method. Otherwise this method does not work.

For details of this security vulnerability, see Perl's case:

http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2005-0448
http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2004-0452

For fileutils.rb, this vulnerability is reported in [ruby-dev:26100].

Removes a file path. This method ignores StandardError if force is true.

No documentation available

Options: force noop verbose

Remove file(s) specified in list. This method cannot remove directories. All StandardErrors are ignored when the :force option is set.

FileUtils.rm %w( junk.txt dust.txt )
FileUtils.rm Dir.glob('*.so')
FileUtils.rm 'NotExistFile', :force => true   # never raises exception

Options: noop verbose

Equivalent to

#rm(list, :force => true)

Options: force noop verbose secure

remove files list[0] list[1]… If list[n] is a directory, removes its all contents recursively. This method ignores StandardError when :force option is set.

FileUtils.rm_r Dir.glob('/tmp/*')
FileUtils.rm_r '/', :force => true          #  :-)

WARNING: This method causes local vulnerability if one of parent directories or removing directory tree are world writable (including /tmp, whose permission is 1777), and the current process has strong privilege such as Unix super user (root), and the system has symbolic link. For secure removing, read the documentation of remove_entry_secure carefully, and set :secure option to true. Default is :secure=>false.

NOTE: This method calls remove_entry_secure if :secure option is set. See also remove_entry_secure.

Options: noop verbose secure

Equivalent to

#rm_r(list, :force => true)

WARNING: This method causes local vulnerability. Read the documentation of rm_r first.

Options: parents, noop, verbose

Removes one or more directories.

FileUtils.rmdir 'somedir'
FileUtils.rmdir %w(somedir anydir otherdir)
# Does not really remove directory; outputs message.
FileUtils.rmdir 'somedir', :verbose => true, :noop => true
An alias for rm_rf

Options: noop verbose mtime nocreate

Updates modification time (mtime) and access time (atime) of file(s) in list. Files are created if they don't exist.

FileUtils.touch 'timestamp'
FileUtils.touch Dir.glob('*.c');  system 'make'

Options: (none)

Returns true if new is newer than all old_list. Non-existent files are older than any file.

FileUtils.uptodate?('hello.o', %w(hello.c hello.h)) or \
    system 'make hello.o'