Ruby File Operations

1. Create a folder
Dir. New % 1
Dir: mkdir # When the full directory name is not specified, the default value is the working directory.
Dir: chdir () change the working directory of the current script
Fileutils. mkdir 'test'
File = file. New ("cmd.txt ")
File. Each do | Line |
Puts line if line = ~ /Target/
End

2. Create a file
Change the current root directory
Dir. chdir ("/home/GUY/sandbox/tmp ")
Dir. chroot ("/home/GUY/sandbox ")
Dir. New % 1
# Dir: rmdir # When the full directory name is not specified, the default value is the working directory.

3. delete an object
Change the current root directory
Dir. chdir ("/home/GUY/sandbox/tmp ")
Dir. chroot ("/home/GUY/sandbox ")
Dir. New % 1
# Dir: rmdir # When the full directory name is not specified, the default value is the working directory.

4. delete folders
# Require 'fileutils'
Fileutils. rm_r (% 1)
5. Delete all folders under a file
Dir: chdir
Dir: Pwd property or dir. getwd ()
# Change the current script working directory

6. Clear folders
Dir: chdir % 1 change the current script working directory
Dir: rmdir # When the full directory name is not specified, the default value is the working directory.
Dir. New % 1
# Require 'ftool'
Fileutils. mkdir 'test'
File = file. New (% 1) # "cmd.txt"
File. Each do | Line |
Puts line if line = ~ /Target/
End

7. Read files
# Require 'ftool'
File. Open (% 1). readlines # 'file name'
# Require 'ftool'
Arr = Io. readlines (% 1) # "myfile"
Lines = arr. Size
# Puts "myfile has # {lines} lines in it ."
# Longest = arr. Collect {| x | X. Length}. Max
# Puts "the longest line in it has # {longest} characters ."

8. Write files
F = open (% 1, "W ")
F. Puts (% 2)

9. Write random files
# Require 'ftool'
File = file. Open (% 1, "W ")
File. Seek (5)
STR = file. Gets # "fghi"
# Require 'ftool'
File. Open ('filename ')
File. Open ("cmd.txt", "R") Do | file |
While line = file. Gets
Puts line
End
End
Puts
File = file. New ("cmd.txt", "R ")
File. each_line do | Line |
Puts line
End
Io. foreach ("cmd.txt") Do | Line |
Puts line if line = ~ /Target/
Puts line if line !~ /Target/
End
###
Dir # POS
Returns the pointer to the current sub-file.
Dir # Pos =
Set the sub-file pointer
Dir # rewind
Set the sub-file pointer to the starting position
Dir # Seek
Set the sub-file pointer
Dir # Tell
Get current pointer

10. Read File Attributes
# Check whether there is content in the file. (If false is returned, there is content. If true is returned, it is null)
File. New ('filename '). Stat. Zero?
# File Size
File. Size? ('Filename ')
Flag1 = filetest: Zero? ("File1 ")
Flag2 = filetest: size? ("File2 ")
Size1 = file. Size ("file1 ")
Size2 = file. Stat ("file2"). Size
###
File: atime (filename)
Returns the last access time of the specified object.

11. Write attributes

12. enumerate all folders in a folder
# Require 'ftool'
Puts dir. glob ('**/*'). Each {| file. downcase}
# Use this method to distinguish between directories and common files
File1 = file. New ("/tmp ")
File2 = file. New ("/tmp/myfile ")
Test1 = file1.directory? # True
Test2 = file1.file? # False
Test3 = file2.directory? # False
Test4 = file2.file? # True
###
Traverse directories
Dir. foreach (% 1) {| entry | puts entry}

13. Copy a folder
Require "fileutils"
Fileutils. CP % 1, % 2

14. Copy all the folders in one directory to another.
# Require 'fileutils'
List = dir. Entries (% 1)
List. each_index do | x |
Fileutils. CP "# {list [x]}", % 2 if! File. directory? (List [x])
End

15. Move folders
# Require 'fileutils'
Fileutils. Mv % 1, % 2

16. move all the folders in one directory to another
# require 'fileutils'
List = dir. entries (% 1)
list. each_index do | x |
fileutils. mv "# {list [x]}", % 2 if! File. directory? (List [x])
end