MS-DOS 6.22 File Search Across Paths Using ATTRIB

MS-DOS 6.22 lacks a dedicated utility like modern Windows' where command, but users frequently rely on the ATTRIB command to locate files across nested directory structures. By leveraging the /S recursive switch, ATTRIB traverses entire directory trees to find matching file patterns and displays their absolute paths. This article explains the syntax, internal directory traversal mechanics, and practical techniques for executing nested file searches using ATTRIB in MS-DOS 6.22.

The Role of ATTRIB in File Searching

The primary purpose of ATTRIB.EXE is to view or alter file attributes: Read-Only (R), Archive (A), System (S), and Hidden (H). However, because ATTRIB supports recursive directory parsing via the /S flag and outputs the complete file path for every match, it doubles as an effective search tool across deeply nested folder structures.

Command Syntax for Searching

To search for files across nested directories, invoke ATTRIB with a target file name or wildcard pattern, accompanied by the /S switch:

ATTRIB [drive:][path][filename] /S
  • Whole-Drive Search: To find a file anywhere on drive C:, start at the root directory: 
    ATTRIB C:\FILENAME.EXT /S
  • Wildcard Searches: To find all files of a specific type (such as batch files): 
    ATTRIB C:\*.BAT /S
  • Targeted Subdirectory Search: To limit the search to a specific branch: 
    ATTRIB C:\DOS\*.SYS /S

Internal Traversal Mechanism

When ATTRIB executes with the /S switch, MS-DOS 6.22 processes the search using a depth-first traversal algorithm:

  1. Initial Query (INT 21h, Function 4Eh): ATTRIB issues a "Find First File" system call using DOS Interrupt 21h, Function 4Eh, specifying the search pattern and matching file attributes.
  2. Sequential Matches (INT 21h, Function 4Fh): It then calls "Find Next File" (Function 4Fh) iteratively until all matching files within the active directory are processed and printed to standard output.
  3. Directory Detection: Once the files in the current directory are evaluated, ATTRIB queries the directory again to find child directory entries (marked by the 0x10 directory attribute bit in the FAT filesystem).
  4. Recursion: For each discovered subdirectory (excluding the . and .. navigational entries), ATTRIB steps into the child directory and repeats the process.
  5. Backtracking: Upon exhausting a directory branch, the program steps back up to the parent directory and moves to the next adjacent branch until the entire subtree has been scanned.

Displaying and Filtering Output

ATTRIB prints the attribute flags on the left, followed by the full drive and directory path of the matched file:

A            C:\AUTOEXEC.BAT
A   R        C:\DOS\ATTRIB.EXE
A  HR        C:\IO.SYS

Because output can scroll off the screen on large disks, pipe the results into the MORE filter:

ATTRIB C:\*.EXE /S | MORE

Alternatively, redirect the search output to a plain text file for review in the MS-DOS Editor:

ATTRIB C:\*.COM /S > C:\RESULTS.TXT

Advantages Over DIR /S

While MS-DOS 6.22 also includes the DIR /S command for recursive listings, ATTRIB /S offers distinct operational differences:

  • Compact Path Output: ATTRIB outputs each match on a single line containing the full path, making it cleaner for redirection and parsing by batch scripts.
  • Attribute Visibility: ATTRIB instantly indicates whether the matched files carry Hidden, System, or Read-Only attributes without requiring additional parameter flags.