remove all files in a directory linux except one code example

Example 1: delete all the files without one in linux

# delete all except the filename

$ rm -v !("filename")

Example 2: remove all files inside directory linux

# remove everything in a directory 
rm /path/to/dir/*
# remove all sub-directories and files
rm -r /path/to/dir/*

Example 3: bash delete everything except

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