Duplicate all the files in a directory with different name (appended string, etc.)

duplicate_all.sh

# Let's say you've .yaml.j2 files in a directory and 
# you want to make copy for each file, for ex:
# files you have : config1.yml.j2 config2.yml.j2 porperties1.yml.j2 setup.yml.j2 
# files you want : config1.yml.j2 config1_new.yml.j2 config2.yml.j2 config2_new.yml.j2 porperties1.yml.j2 porperties1_new.yml.j2 setup.yml.j2 setup_new.yml.j2 

for filename in *.yml.j2; do mv $filename ${filename%.yaml.j2}_new.yml.j2; done