I never thought of 
grep $i=!$i,

[download]
before. I usually use 
grep $i^=$i,

[download]

Yours is easier to understand, though.

Update: Yeah, I mean grep $i^=1,.

In reply to Re^3: Split a string based on change of character by ikegami
in thread Split a string based on change of character by eyepopslikeamosquito

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