rename Command in Linux: Batch Rename Files

Q: How do I change file extensions in bulk?

Use a substitution pattern: rename 's/ .jpeg$/.jpg/' *.jpeg. The regex matches the old extension at the end of the name and replaces it.

Q: How do I rename files without the rename command?

Use a loop with mv and basename: for f in *.jpeg; do mv '$f' '$(basename '$f' .jpeg).jpg'; done. This is portable across systems that lack rename.

Quick take: The rename command renames many files at once using patterns. The Perl version uses regex: rename 's/\.jpeg$/.jpg/' *.jpeg changes every .jpeg to .jpg. Add -n to preview before committing.

Introduction

While mv renames one file at a time, the rename command renames many at once using patterns — perfect for changing extensions, fixing naming schemes, or replacing text across a batch of files. Note that two versions exist: the powerful Perl-based rename common on Debian/Ubuntu, and a simpler util-linux version elsewhere.

Syntax

The basic syntax of the rename command is:

rename [OPTIONS] 's/OLD/NEW/' FILES   # Perl version

Common Options and Parameters

The most useful options and parameters for the rename command:

Option	Description
-n	Dry run — show what would be renamed without doing it.
-v	Verbose — print each rename as it happens.
-f	Force — overwrite existing files.
's/old/new/'	Perl substitution applied to each filename.
'y/A-Z/a-z/'	Transliterate (e.g. uppercase to lowercase).

Practical Examples

Real rename commands you can run today:

# Preview changing .jpeg to .jpg
rename -n 's/\.jpeg$/.jpg/' *.jpeg
# Actually change the extension
rename 's/\.jpeg$/.jpg/' *.jpeg
# Replace spaces with underscores
rename 's/ /_/g' *
# Lowercase all filenames
rename 'y/A-Z/a-z/' *
# Add a prefix to files
rename 's/^/2026_/' *.txt

Tips and Best Practices

Always run with -n first to preview the renames — pattern mistakes can rename far more than you intended.
Check which rename you have: rename --version. The Perl version takes a regex; the util-linux version takes rename from to files.
For one-off renames, plain mv old new is simpler; reach for rename when changing many files by pattern.

Final Thoughts

rename brings pattern power to file renaming, turning a tedious loop into a single command — changing extensions, fixing spaces, or re-casing names en masse. Always preview with -n, confirm which version you have, and keep mv for single files. For complex cases, a for loop with basename remains a portable fallback.

FAQ: rename Command in Linux

How do I rename multiple files at once in Linux?+

Use the rename command with a pattern. On Debian/Ubuntu, rename 's/\.txt$/.md/' *.txt changes every .txt to .md. Always test with -n first to preview the changes.

How do I change file extensions in bulk?+

Use a substitution pattern: rename 's/\.jpeg$/.jpg/' *.jpeg. The regex matches the old extension at the end of the name and replaces it.

How do I preview renames before applying them?+

Add -n (dry run): rename -n 's/old/new/' * prints what would be renamed without changing anything, so you can confirm the pattern is correct.

Why does my rename command behave differently?+

There are two versions: the Perl-based rename (Debian/Ubuntu) takes a regex, while the util-linux version uses rename from to files. Run rename --version to see which you have.

How do I rename files without the rename command?+

Use a loop with mv and basename: for f in *.jpeg; do mv "$f" "$(basename "$f" .jpeg).jpg"; done. This is portable across systems that lack rename.

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