Group rename by file type means modifying the names of multiple files at once, specifically targeting files sharing the same extension (like .jpg, .docx, or .txt). This operation uses the file extension as a filter to select only certain files from a larger group for renaming. It differs from general bulk renaming because it focuses exclusively on files of a specified type, leaving other files in the folder unchanged, and typically ensures the file extension itself remains intact unless explicitly changed during the process.

For instance, photographers might select all .CR2 raw image files from an event and rename them uniformly using a pattern like "Wedding_Shoot_001.CR2", "Wedding_Shoot_002.CR2" to replace generic camera filenames. Similarly, a software developer could locate all .log files in a directory and append the current date (e.g., "system_log_20241015.log") for easier archival. This is commonly performed using dedicated batch rename utilities (e.g., Bulk Rename Utility, Advanced Renamer), file managers like Explorer or Finder with extensions, or scripting (PowerShell, Bash).

This approach saves significant time over manual renaming. However, caution is needed to avoid accidentally overwriting files with identical new names. While it ensures consistent naming within a file type group, relying solely on extension filters carries risk if different file types share the same extension incorrectly. Good practice involves verifying selections before applying changes. Future tools might incorporate AI for smarter grouping beyond simple extensions.