$ perl -E 'say join(" ", split /(..)/, "e58c97e4bab0") =~ s/^\s+//r'
e5  8c  97  e4  ba  b0

$ perl -E 'say join(" ", split /(..)/, "e58c97e4bab0") =~ s/^\s+//r =~ y/ / /rs'
e5 8c 97 e4 ba b0