COMPACT: Displays or alters the compression of files on NTFS partitions.

Microsoft Windows [Version 10.0.19045.3693]
(c) Copyright 1985-2023 Microsoft Corp.

C:\\WINDOWS>

Displays or alters the compression of files on NTFS partitions.

COMPACT [/C | /U] [/S[:dir]] [/A] [/I] [/F] [/Q] [filename [...]]

  /C        Compresses the specified files.  Directories will be marked
            so that files added afterward will be compressed.
  /U        Uncompresses the specified files.  Directories will be marked
            so that files added afterward will not be compressed.
  /S        Performs the specified operation on files in the given
            directory and all subdirectories.  Default "dir" is the
            current directory.
  /A        Displays files with the hidden or system attributes.  These
            files are omitted by default.
  /I        Continues performing the specified operation even after errors
            have occurred.  By default, COMPACT stops when an error is
            encountered.
  /F        Forces the compress operation on all specified files, even
            those which are already compressed.  Already-compressed files
            are skipped by default.
  /Q        Reports only the most essential information.
  filename  Specifies a pattern, file, or directory.

  Used without parameters, COMPACT displays the compression state of
  the current directory and any files it contains. You may use multiple
  filenames and wildcards.  You must put spaces between multiple
  parameters.

The `COMPACT` command in Windows Command Prompt is used to control the compression of files or directories on NTFS partitions. Here are some examples with comments: Example 1: Compress file:

COMPACT /C file.txt

Description: This command compresses the file "file.txt" on an NTFS partition. The `/C` option stands for "compress". Example 2: Uncompress file:

COMPACT /U file.txt

Description: `/U` is used to decompress the file "File.txt". Note that this will restore the file to its original state. Example 3: Compress all files in a directory:

COMPACT /C /S: files

Description: Here all files in the "Files" directory and its subdirectories are compressed. The `/S` option stands for "include all subdirectories". Example 4: Uncompress all files in a directory:

COMPACT /U /S: files

Description: All files in the Files directory and its subdirectories are decompressed using `/U`. Example 5: Show compression status:

COMPACT /I

Description: This command displays the status of file compression on the current drive. Example 6: Disable compression for a directory:

COMPACT /I /F:OFF Directory

Description: `/F:OFF` disables compression for the directory. This can be useful if you want to turn off compression for specific files or directories. Example 7: Compress all files on the drive:

COMPACT /C /EXE:LZX /I /F:ON C:\

Description: This command compresses all executable files on C drive using LZX algorithm. Note that this can be for the entire drive and compressing system files can be risky. Example 8: Force compression on a directory:

COMPACT /C /FORCE directory

Description: `/FORCE` forces compression on the directory regardless of whether it is already compressed. Example 9: Compress all files in current directory:

COMPACT /C /A

Description: Here all files in the current directory are compressed. The `/A` option stands for "All Files". Example 10: Undo file compression:

COMPACT /U /EXE:LZX file.exe

Description: `/U` is used to decompress the file "File.exe". Note that the compression method used (here: LZX) can be specified. It is important to note that there are risks to using 'COMPACT', especially if used improperly. It is advisable to ensure that important files and system files are not unintentionally affected.

There are a few points to note when using the `COMPACT` command in the Windows Command Prompt: 1. For NTFS only: The `COMPACT` command is specific to the NTFS file system. It doesn't work on FAT32 or exFAT. Make sure the target drive is formatted NTFS before using `COMPACT`. 2. Potential Data Loss: Compressing files may result in some data loss. This is because compressed files are no longer in their original state, and therefore certain file types (such as already compressed files) may not be able to be further compressed. 3. Compatibility: Some applications or processes may not be able to handle compressed files. Make sure that compression does not negatively impact the proper functioning of your applications. 4. System Files: Compressing system files may cause instability or malfunction. Be careful when trying to compress system files or files in the Windows directory. 5. Storage Savings: Actual storage space savings from file compression may vary depending on the file type. Large media files (e.g. JPEG images or already compressed videos) may not achieve significant savings. 6. Performance: Reading and writing compressed files may be slightly slower than uncompressed files because the files may need to be decompressed or compressed before reading or writing. 7. Use Options: Be sure to use the `COMPACT` options carefully to achieve the desired results. In particular, the `/F` option (Force) and `/A` option (All files) can have strong effects. 8. Data Recovery: Make sure you have a reliable data backup before performing extensive file compression. This allows you to restore the original data in case of unexpected problems. 9. Missing Privileges: Make sure you have the necessary permissions to access the files you want to compress or decompress. Administrator privileges may be required, especially if system files are affected. 10. Storage Space Monitoring: Monitor the available space on your drive, especially when compressing large amounts of files. Expected storage space savings can be monitored to ensure desired results are achieved. By keeping these points in mind, you can use the `COMPACT` command effectively and safely. As with all commands that make changes to the file system, it is important to proceed with caution and be aware of the potential impact.