[SOLVED] How to split a string with an uniq substring in bash?

Issue

I have a string:

str="...AAA..."

I want to split it to 3 substring variables sub1, sub2, sub3. The string AAA is sub2 and is an unique pattern which won't appear in sub1 and sub3. And all the other characters were saved in sub1 and sub3. Only one extreme situation is that AAA may appear at the end when sub3 needs to be an empty string. How can I achieve this, maybe using grep, sed or gawk?

Solution

You don't need grep, sed, or awk. Just use Shell Parameter Expansion with % and #:

str="ABCAAAXYZ"
sub2="AAA"

sub1="${str%${sub2}*}"
sub3="${str#*${sub2}}"

printf '%s\n' "$sub1" "$sub2" "$sub3"

ABC
AAA
XYZ

This works just the same with str="ABCAAA" or str="AAAXYZ".

Answered By - pmf

Answer Checked By - Marie Seifert (WPSolving Admin)