# rename > Rename multiple files. > NOTE: this page refers to the command from the `perl-rename` Arch Linux package. > More information: . - Rename files using a Perl Common Regular Expression (substitute 'foo' with 'bar' wherever found): `rename {{'s/foo/bar/'}} {{*}}` - Dry-run - display which renames would occur without performing them: `rename -n {{'s/foo/bar/'}} {{*}}` - Force renaming even if the operation would remove existing destination files: `rename -f {{'s/foo/bar/'}} {{*}}` - Convert filenames to lower case (use `-f` in case-insensitive filesystems to prevent "already exists" errors): `rename 'y/A-Z/a-z/' {{*}}` - Replace whitespace with underscores: `rename 's/\s+/_/g' {{*}}`