batch-file-rename

Batch file renaming utility with pattern matching, regex, sequence numbering, and dry-run preview. Supports prefix/suffix, case conversion, whitespace cleanup, and recursive directory processing.

Rename multiple files using flexible patterns with safe dry-run preview.

When to Use

• Bulk rename files in a directory (photos, downloads, exports)
• Normalize file names (trim whitespace, lowercase, replace separators)
• Add sequence numbers (e.g., 001-file.txt, 002-file.txt)
• Replace patterns with regex across many files
• Process directories recursively

Prerequisites

• No external dependencies — uses only shell builtins and sed/awk

Basic Steps

1. Dry-run preview (always do this first)

bash

# Preview rename with prefix + sequence number
for f in *.txt; do
  [ -f "$f" ] || continue
  echo "Would rename: $f → photo-001-$f"
done

2. Prefix + sequence number

bash

i=1
for f in *.jpg *.png; do
  [ -f "$f" ] || continue
  printf -v new "vacation-%03d-%s" "$i" "$f"
  echo "Renaming: $f → $new"
  mv -- "$f" "$new"
  ((i++))
done

3. Regex pattern replace

bash

# Replace spaces with underscores, lowercase everything
for f in *; do
  [ -f "$f" ] || continue
  new=$(echo "$f" | tr '[:upper:] ' '[:lower:]_' | sed 's/[^a-z0-9._-]/_/g' | sed 's/_\+/_/g')
  [ "$f" != "$new" ] && mv -- "$f" "$new" && echo "$f → $new"
done

4. Strip prefix from all files

bash

for f in report-*.pdf; do
  [ -f "$f" ] || continue
  new="${f#report-}"
  mv -- "$f" "$new" && echo "$f → $new"
done

5. Recursive rename in subdirectories

bash

find . -type f -name "*.tmp" | while read -r f; do
  dir=$(dirname "$f")
  base=$(basename "$f" .tmp)
  new="$dir/$base.txt"
  mv -- "$f" "$new" && echo "$f → $new"
done

Key Safety Rules

1. Always dry-run first — replace mv with echo "Would rename:" and verify output
2. Quote variables — "$f" not $f (handles spaces and special chars)
3. Use -- in mv — mv -- "$f" "$new" prevents option injection
4. Backup first — tar czf backup.tar.gz *.txt before bulk operations
5. Check collisions — if two files map to the same name, the rename will fail or overwrite

Example: Normalize Downloads Folder

bash

cd ~/Downloads
# Dry run
for f in *; do
  [ -f "$f" ] || continue
  new=$(echo "$f" | tr '[:upper:] ' '[:lower:]_' | sed 's/[^a-z0-9._-]/_/g')
  echo "$f → $new"
done
# After verifying, apply:
for f in *; do
  [ -f "$f" ] || continue
  new=$(echo "$f" | tr '[:upper:] ' '[:lower:]_' | sed 's/[^a-z0-9._-]/_/g')
  [ "$f" != "$new" ] && mv -- "$f" "$new"
done

Example: Sequential Numbering for Photos

bash

i=1
for f in IMG_*.JPG; do
  [ -f "$f" ] || continue
  printf -v new "trip-2026-%03d.JPG" "$i"
  mv -- "$f" "$new"
  ((i++))
done