import re

# multiline string
string = '#kernel-generic.*\n#kernel-huge.*\n#kernel-modules.*\n#kernel-source'

# matches all whitespace characters
## from pythex.org   -->   ^#(kernel-.+)$
#pattern = r'^#(kernel-.+)$\1'
#replace = r'\1'

#pattern = r'^#(kernel)\1'
#replace = r'\1'

## works
#pattern = r'#(kernel)'
#replace = r'kernel'

## works
pattern = r'#kernel'
replace = r'kernel'

#pattern = r'(#kernel)\1'
#replace = r'ola'


new_string = re.sub(pattern, replace, string) 
print(string)
print('')
print(new_string)


##########
##s = 'Python Python is awesome'
##
##pattern = r'(\w+)\s+\1'
##replace = r'\1'
##
###new_s = re.sub(r'(\w+)\s+\1', r'\1', s)
##new_s = re.sub(pattern, replace, s)
##
##print(new_s)