$ perl -le " for( @ARGV ){ print; s{(.)}{$1.++$counter}ge; print}  " abc XYZ
abc
a1b2c3
XYZ
X4Y5Z6


## perl -pTe "s{(core:para edpnum-start=\x22)}{$1.++$counter}ge;  " < test.xml > testcounted.xml

## perl -pi.orig -Te "s{(core:para edpnum-start=\x22)}{$1.++$counter}ge;  " test.xml
## diff -u test.orig test.xml