# repren > Multi-pattern string replacement and file renaming tool. > More information: . - Do a dry-run renaming a directory of PNGs with a literal string replacement: `repren --dry-run --rename --literal --from '{{find_string}}' --to '{{replacement_string}}' {{*.png}}` - Do a dry-run renaming a directory of JPEGs with a regular expression: `repren --rename --dry-run --from '{{regular_expression}}' --to '{{replacement_string}}' {{*.jpg}} {{*.jpeg}}` - Do a find-and-replace on the contents of a directory of CSV files: `repren --from '{{([0-9]+) example_string}}' --to '{{replacement_string \1}}' {{*.csv}}` - Do both a find-and-replace and a rename operation at the same time, using a pattern file: `repren --patterns {{path/to/patfile.ext}} --full {{*.txt}}` - Do a case-insensitive rename: `repren --rename --insensitive --patterns {{path/to/patfile.ext}} *`