3 Ways to Delete All Files in a Directory Except One or Few Files with Extensions

The different extended pattern matching operators are listed below, where pattern-list is a list containing one or more filenames, separated using the | character:

1. *(pattern-list) – matches zero or more occurrences of the specified patterns
2. ?(pattern-list) – matches zero or one occurrence of the specified patterns
3. +(pattern-list) – matches one or more occurrences of the specified patterns
4. @(pattern-list) – matches one of the specified patterns
5. !(pattern-list) – matches anything except one of the given patterns

To use them, enable the extglob shell option as follows:

# shopt -s extglob

1. To delete all files in a directory except filename, type the command below:

$ rm -v !("filename")

2. To delete all files with the exception of filename1 and filename2:

$ rm -v !("filename1"|"filename2") 

Source: 3 Ways to Delete All Files in a Directory Except One or Few Files with Extensions