Real life data tends to get corrupted because machines (and humans) are never as reliable as hoped. One efficient way is make sure your data 100% correct is to generate some kind of hash. That hash shall be unique, compact and efficient.

What You Need

• The file(s) you downloaded (e.g., your_data.file)
• The MD5 checksum file (e.g., md5sum.txt) which contains one line per file, in this format:

  25e800aae700a9a1f20f3ae28f5ccc96 your_data.file

• Note: There are TWO spaces between the checksum(s) and the filename(s)

Linux Instructions

1. Open Terminal
   • Press Ctrl + Alt + T, or find Terminal in your applications menu
2. Navigate to your data folder
   • Type cd followed by the path to your folder
   • For example: cd /path/to/data-files
3. Verify the checksum
   • Type: md5sum -c md5sum.txt
   • Press Enter
   • You should see: your_data.file: OK
   • If it doesn't match, you'll see: your_data.file: FAILED

macOS Instructions

1. Open Terminal
   • Press Command + Space
   • Type "Terminal"
   • Press Enter
2. Navigate to your data folder
   • Type cd followed by the path to your folder
   • For example: cd /path/to/data-files
3. Verify the checksum
   • Type: md5 -c md5sum.txt
   • Press Enter
   • You should see: your_data.file: OK
   • If it doesn't match, you'll see: your_data.file: FAILED

Windows Instructions

1. Open Command Prompt
   • Press the Windows key + R
   • Type cmd and press Enter
2. Navigate to your data folder
   • Type cd followed by the path to your folder
   • For example: cd C:\path\to\data-files
3. Verify the checksum
   • Type: certutil -hashfile lims-samples-labels.docx MD5
   • Press Enter
   • Compare the displayed checksum with the one in your md5sum.txt file
   • They must match exactly, character by character

Note: Windows doesn't have a built-in command to directly verify against a checksum file. You'll need to compare the numbers manually.

Common Issues

• "Command not found"
  • Windows: Make sure you're using Command Prompt, not PowerShell
  • macOS/Linux: Your terminal might be in the wrong directory
• "File not found"
  • Make sure both the data file and checksum file are in the same folder
  • Check that the filenames match exactly, including case
  • File names are case-sensitive on macOS and Linux
• "FAILED" or checksums don't match
  • Your download might be incomplete or corrupted
  • Try downloading the file again
  • Check that the checksum file hasn't been modified

Need Help?

• Make sure both files are in the same folder
• Check that the filenames in the checksum file match your actual files exactly
• On Linux/macOS, make sure there are exactly two spaces between the checksum and filename
• If verification fails, try downloading both files again