Ruby Dir Class and Methods

The Dir class in Ruby represents directories in your file system. It provides several class methods for handling directories.

1. Create a directory

The mkdir method can be used to create a new directory:

Dir.mkdir('new_directory')

2. Delete a directory

The delete or rmdir method can be used to delete a directory:

Dir.delete('directory_to_delete')
# or
Dir.rmdir('directory_to_delete')

Note that the directory must be empty to delete it.

3. Change the current directory

You can change the current directory using the chdir or cd method:

Dir.chdir('/path/to/new/directory')
# or
Dir.cd('/path/to/new/directory')

4. List directories and files

The entries method returns an array of filenames in a directory:

files = Dir.entries('/path/to/directory')
files.each do |file|
  puts file
end

You can also use the glob method to match filenames using a pattern:

files = Dir.glob('*.txt') # Get all .txt files in current directory
files.each do |file|
  puts file
end

5. Get the current directory

The pwd or getwd method returns the path of the current directory:

puts Dir.pwd
# or
puts Dir.getwd

6. Working with temporary directories

The mktmpdir method in Dir::Tmpname module creates a temporary directory:

require 'tmpdir'

temp_dir = Dir.mktmpdir
puts temp_dir # Outputs: path to a newly created temporary directory

Remember to delete the temporary directory once you're done with it.

7. Iterate over directories and files

The foreach method executes a block of code for each entry in a directory:

Dir.foreach('/path/to/directory') do |file|
  puts file
end

Note: The . and .. entries represent the current directory and parent directory respectively.

These are just a few of the most commonly used methods in the Dir class. For more advanced usage, refer to the Ruby documentation.

List files in a directory with Ruby Dir class:
- Description: The Dir.entries method can be used to list all files and directories in a given directory.
- Code example:
```
files = Dir.entries('/path/to/directory')
puts files
```
Ruby Dir class example:
- Description: The Dir class provides methods for working with directories in Ruby.
- Code example:
```
# List files in the current directory
files = Dir.entries('.')
puts files
```

Working with directories in Ruby:

Description: Ruby's Dir class provides methods for working with directories, such as creating, removing, or checking if a directory exists.

Code example:

# Create a directory
Dir.mkdir('my_directory')

# Remove a directory
Dir.rmdir('my_directory')

# Check if a directory exists
if Dir.exist?('my_directory')
  puts 'The directory exists.'
else
  puts 'The directory does not exist.'
end

Ruby Dir glob method:
- Description: The Dir.glob method allows you to retrieve files matching a specific pattern.
- Code example:
```
# List all Ruby files in the current directory
ruby_files = Dir.glob('*.rb')
puts ruby_files
```
How to navigate directories in Ruby:
- Description: Use the Dir.chdir method to change the current working directory.
- Code example:
```
# Change to a different directory
Dir.chdir('/path/to/new_directory')

# Print the current working directory
puts Dir.pwd
```

Recursively list files with Ruby Dir:

Description: Combine Dir.glob with File.join to recursively list files in subdirectories.

Code example:

# Recursively list all Ruby files in the current directory and subdirectories
all_ruby_files = Dir.glob('**/*.rb', base: '.')
puts all_ruby_files

Filtering files with Ruby Dir class:

Description: Use methods like select to filter files based on specific criteria.

Code example:

# List only files (excluding directories) in the current directory
files_only = Dir.entries('.').select { |f| File.file?(f) }
puts files_only

Sorting files in a directory with Ruby:
- Description: Use sort or sort_by to sort files in a directory.
- Code example:
```
# List and sort all files in the current directory
sorted_files = Dir.entries('.').sort
puts sorted_files
```
Getting the current working directory in Ruby:
- Description: The Dir.pwd method returns the current working directory.
- Code example:
```
current_directory = Dir.pwd
puts "Current working directory: #{current_directory}"
```
Changing directories in Ruby:
- Description: Use Dir.chdir to change the current working directory.
- Code example:
```
# Change to a different directory
Dir.chdir('/path/to/new_directory')
```
Checking if a directory exists with Ruby Dir:
- Description: The Dir.exist? method checks if a directory exists.
- Code example:
```
if Dir.exist?('my_directory')
  puts 'The directory exists.'
else
  puts 'The directory does not exist.'
end
```
Using Dir class for file operations in Ruby:
- Description: The Dir class provides methods for various file operations, such as creating, removing, or listing files in a directory.
- Code example:
```
# List all files in the current directory
files = Dir.entries('.')
puts files

# Create a new directory
Dir.mkdir('new_directory')

# Remove a directory
Dir.rmdir('new_directory')
```
Iterating through files in a directory using Ruby Dir:
- Description: Use Dir.foreach to iterate through files in a directory.
- Code example:
```
# Iterate through files in the current directory
Dir.foreach('.') do |file|
  puts file
end
```