How to Rename Files Using mmv for Advanced Renaming

The mmv command is a versatile utility for moving, renaming, copying, or linking multiple files by matching filename patterns. It simplifies batch file operations that would otherwise require loops or more complex scripting.

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Install mmv (if not pre-installed)

# Debian/Ubuntu
sudo apt install mmv

# Fedora
sudo dnf install mmv

# macOS (via Homebrew)
brew install mmv

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Basic Syntax

mmv [options] 'source_pattern' 'target_pattern'

Use single quotes (') to prevent shell expansion of wildcards like * or ?.

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Common Use Cases

1. Rename Files with a Pattern

Replace all .txt extensions with .md:

mmv '*.txt' '#1.md'

• #1 captures the wildcard match from the source pattern (e.g., file1.txt → file1.md).

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2. Add a Prefix to Filenames

Add backup_ to all .jpg files:

mmv '*.jpg' 'backup_#1.jpg'

• Example: photo.jpg → backup_photo.jpg.

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3. Change Filename Case

Convert all .JPG filenames to lowercase:

mmv '*.JPG' '#1.jpg' -l

• Use -l for lowercase or -u for uppercase.

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4. Replace Substrings

Replace underscores _ with hyphens - in filenames:

mmv '*_*' '#1-#2'

• Example: report_2023.txt → report-2023.txt.

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5. Sequential Numbering

Rename all .png files to image_1.png, image_2.png, etc.:

mmv '*.png' 'image_#1.png' -n 1

• -n 1 starts numbering at 1.

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6. Copy Files (Instead of Move)

Copy all .conf files to .conf.bak:

mmv -c '*.conf' '#1.conf.bak'

• -c: Copy instead of move.

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7. Delete Substrings

Remove temp_ from filenames:

mmv 'temp_*' '#1'

• Example: temp_data.csv → data.csv.

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Advanced Options

• Dry Run: Preview changes without executing (-n):

  mmv -n '*.log' '#1.log.bak'

• Verbose Mode: Show detailed output (-v):

  mmv -v '*.txt' '#1.md'

• Symbolic Links: Create links instead of moving (-l):

  mmv -l '*.sh' 'scripts/#1'

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Handling Spaces/Special Characters

Use \ to escape spaces or special characters:

mmv 'file\ with\ spaces*.txt' 'new_#1.txt'

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Caveats

• mmv overwrites files by default. Use -n to test first.
• For more complex regex, consider the rename command (Perl-based).

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Alternatives

• rename (Perl):

  rename 's/\.jpeg$/\.jpg/' *.jpeg

• find + xargs:

  find . -name "*.txt" -print0 | xargs -0 -I {} mv {} {}.bak