The COMP command in Windows Command Prompt is a file-comparison tool used to compare the contents of two files or sets of files, byte-by-byte. It is primarily used to determine if there are any differences between files, which is particularly useful in tasks such as verifying copies or understanding changes over time in data sets.


The basic syntax for using COMP is:

COMP [data1] [data2] [options]
  • data1: Specifies the location and name of the first file or set of files to compare.
  • data2: Specifies the location and name of the second file or set of files to compare.


  • /D: Display differences in decimal format. The default is hexadecimal.
  • /A: Display differences as ASCII characters.
  • /L: Display line numbers for differences.
  • /N=number: Compare only the first specified number of lines in each file.
  • /C: Ignore the case of alphabet characters when comparing files.
  • /OFF[line]: Do not skip files with offline attribute set.


  1. Compare Two Files:

    COMP file1.txt file2.txt

    This command compares file1.txt with file2.txt and shows the differences in hexadecimal format.

  2. Compare Files in ASCII and Display Line Numbers:

    COMP /A /L file1.txt file2.txt

    Use this command to see differences as ASCII characters with line numbers indicated.

  3. Compare First 100 Lines of Two Files:

    COMP /N=100 file1.txt file2.txt

    This example focuses the comparison on the first 100 lines of each file.

  4. Case Insensitive Comparison:

    COMP /C file1.txt file2.txt

    Compares the two specified files without regard for case sensitivity.

Common Issues

  • Files Not Found: Ensure paths provided to the command are correct and both files exist.
  • Access Permissions: Execution might fail if the command lacks the necessary permissions to read one or both files.


Integrating COMP with other CMD commands can enhance file management and monitoring tasks. Here’s an example script that compares files and then uses ECHO to output the result:

COMP file1.txt file2.txt > comp_result.txt
    ECHO No differences found.
) ELSE (
    ECHO Differences detected. Check comp_result.txt for details.
  • FC: Another file comparison tool that can also compare content in text format and offers a bit more flexibility in textual comparison.
  • XCOPY: Useful for copying files and directories with various options for comparison and backup purposes.

For learning more about these commands, you can always check the built-in help by typing HELP <command> in CMD or visiting Microsoft’s official documentation online.