Bash: String manipulation

For this example string: 

my_string="example.string.with.dots"

%: Remove match from last occurrence

echo "${my_string%.*}" # --> example.string.with

%%: Remove match from first occurrence

echo "${my_string%%.*}" # --> example

#: Remove match until first occurrence

echo "${my_string#*.}" # --> string.with.dots

##: Remove match until last occurrence

echo "${my_string##*.}" # --> dots

/n/n: Substitute one occurrence of the longest possible match

echo "${my_string/*./,}" # --> ,dots

//n/n: Substitute all occurrences of the longest possible match

echo "${my_string//?./,}" # --> exampl,strin,wit,dots

source: Baeldung