Random Characters Rule

Want to add random characters to files to prevent duplicates? Need to generate test file numbers? Just one click.

What This Feature Can Help You With

• Batch process files to prevent duplicates: Downloaded a bunch of identical files and want to add random numbers to distinguish them
• Generate test file numbers: Want to add random codes to test data and temporary files to prevent overwriting
• Add identifiers to backup files: Add random suffixes to backup files to easily identify different versions
• Change filename only: Keep extensions like .jpg and .txt unchanged, add random characters only to the filename

Quick Start (3 Steps)

1. Click the "Add Rule" button → Select "Random Padding"
2. Fill in two fields:
   • Random Length: For example 6 (how many random characters to add)
   • Random Characters: Check the character types you want (numbers, letters, etc.)
3. Click preview first to see the effect, then click apply if everything looks good, to avoid accidentally changing a batch of files incorrectly

Concrete Examples

Example 1: Batch Add Numeric Random Codes

❌ Original file: document.pdf、document.pdf、document.pdf... 😫 Problem: Downloaded multiple identical files and want to add random numbers to distinguish them

✅ Operation:

• Random Length: 4
• Random Characters: Check Numbers 0-9
• Insert Position: Select Suffix

✅ Result: document_7392.pdf、document_1584.pdf、document_9263.pdf...

Why set it up this way: 4 digits provide 10,000 combinations, enough to prevent daily file duplicates, and numeric codes are concise and easy to read.

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Example 2: Mixed Character Random Identifier

❌ Original file: backup.zip、backup.zip、backup.zip... 😫 Problem: Same batch of backup files, want to add more complex random identifiers

✅ Operation:

• Random Length: 6
• Random Characters: Check Numbers 0-9 + Uppercase A-Z
• Insert Position: Select Prefix

✅ Result: A7K2M9_backup.zip、B3N8Q1_backup.zip、C9P4R7_backup.zip...

Why set it up this way: Combining numbers and uppercase letters provides more possibilities (36 to the 6th power), 6 characters ensures high uniqueness, and prefix position makes sorting easier.

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Example 3: Chinese Numeric Random Sequence

❌ Original file: 报告.docx、报告.docx、报告.docx... 😫 Problem: Chinese filename, want to add Chinese numeric random codes

✅ Operation:

• Random Length: 2
• Random Characters: Check Chinese Lowercase Numbers
• Insert Position: Select Suffix

✅ Result: 报告_五八.docx、报告_三一.docx、报告_九二.docx...

Why set it up this way: Chinese numbers are more in line with reading habits in Chinese environments, 2 characters strike a balance between readability and randomness.

Content to Fill In

Basic Settings

• Random Length How many random characters you want to generate, for example 4, 6, 8 (Range 1-100, larger numbers mean stronger randomness but longer filenames)

• Random Characters Check the character types you want to use, you can check multiple at the same time:

  • Numbers 0-9: Most concise, checked by default
  • Lowercase a-z: Lowercase English
  • Uppercase A-Z: Uppercase English
  • Chinese Lowercase Numbers: zero one two three four five six seven eight nine ten
  • Chinese Uppercase Numbers: 零壹贰叁肆伍陆柒捌玖拾

• Custom Want to use special characters? Check this, then type the characters you want (For example, fill in @#$%, random characters will be selected from these)

Advanced Options (You Don't Need to Worry About These, Defaults Are Fine)

• Insert Position Choose where to add random characters in the filename:

  • Prefix: Add at the beginning, like A7K2M9_filename.txt
  • Suffix (default): Add at the end (before extension), like filename_A7K2M9.txt
  • Replace Filename: Replace the entire filename with random characters
  • Absolute Position: Insert at the character position number
  • Before Specific Text: Insert before certain specific text
  • After Specific Text: Insert after certain specific text
  • Replace Text: Replace a segment of text in the filename with random characters

• Ignore Extension Checked by default, only change the filename, don't touch .jpg, .txt and other suffixes. If you really need to add random characters to the extension as well, you can uncheck this option.

Frequently Asked Questions

❓ Does the preview result change every time?

This is normal, random characters are generated randomly each time. The moment you click "Apply" is when they're fixed.

Tip: If you're not satisfied with the previewed random result, you can click the "Apply Rule" button multiple times to generate different random characters until you're satisfied.

Recommendation: If you want predictable numbering, the Sequence Generation Rule is more suitable.

❓ Custom characters were filtered out?

The system automatically filters illegal characters that filenames don't support (\ / : * ? " < > |), to ensure valid filenames.

Solution: Avoid filling these symbols in your custom characters.

❓ What if random characters repeat?

Theoretically, repetition is possible (with very small probability).

Solution:

1. Increase random length (for example, change from 4 to 6 digits)
2. Expand character types (check both numbers and letters)

❓ Chinese characters display abnormally?

Make sure your system supports Chinese display, some platforms may have limitations on Chinese filenames.

Advanced Techniques

• ✅ Combine with "Sequence Generation": Sequence ensures order, random characters prevent duplicates, double insurance for file uniqueness
• ✅ Combine with "Date and Time": Time stamps mark batches, random characters distinguish files within the same batch
• ✅ Combine with "Insert Text": First insert a fixed prefix (for example backup_), then add random characters, construct complete identifiers

What to Look at Next?

• Sequence Generation: Provides predictable ordered numbering, complements random characters
• Insert Text: Add fixed identifiers, use in combination with random characters
• Date and Time: Create random identifiers with time stamps by combining with time