perl + add rule to perl one line command

The following Perl syntax replaces OLD with NEW, but not if 开发者_开发知识库a digit exists before or after the OLD word.

 OLD=ABBA1 ; export OLD
 NEW=OBAMA1 ; export NEW

 perl -i -pe 'next if /^ *#/; s/(\b|\D)$ENV{OLD}(\b|\D)/$1$ENV{NEW}$2/g' file

My question:

I also not want to replace the OLD with NEW if a-z or A-Z letters exist before or after OLD word.

Please advise how to change my Perl syntax in order to do that?

Examples (of which OLD word need to replace with NEW):

ABBA1R  - not replace
QABBA1  - not replace
ABBA1W  - not replace
@ABBA1  - replace ABBA1 with OBAMA1
ABBA1=  - replace ABBA1 with OBAMA1
ABBA1w  - not replace
4ABBA1  - not replace
ABBA11  - not replace
e  ABBA1  - replace ABBA1 with OBAMA1  (remark between e to ABBA1 I have space)
ABBA1 p   - replace ABBA1 with OBAMA1  (remark between ABBA1 to p I have space)
?ABBA1    - replace ABBA1 with OBAMA1
_ABBA1_   - replace ABBA1 with OBAMA1

---

This works for me:

OLD=ABBA1 ; export OLD
NEW=OBAMA1 ; export NEW

perl -pe 'next if /^ *#/;
          s/(\b|[[:^alnum:]])$ENV{OLD}(\b|[[:^alnum:]])/$1$ENV{NEW}$2/g' <<!

ABBA1R  - not replace
QABBA1  - not replace
ABBA1W  - not replace
@ABBA1  - replace
ABBA1=  - replace
ABBA1w  - not replace
4ABBA1  - not replace
ABBA11  - not replace
e  ABBA1  - replace  (remark between e to ABBA1 I have space)
ABBA1 p   - replace   (remark between ABBA1 to p I have space)
?ABBA1    - replace
_ABBA1_   - replace

!

It's a shell script - I removed the '-i' option since there isn't a file to overwrite (and I want to see the result).

The original script with the (\b|\D) constructs were odd; the '\D' part (non-digit) allows an alphabetic character to precede the match. The change to use just '(\b|[[:^alnum:]])' twice insists on a word boundary or a non-alphanumeric character. The word boundary matters at the beginning or end of a line. The captures are now needed.

Output

ABBA1R  - not replace
QABBA1  - not replace
ABBA1W  - not replace
@OBAMA1  - replace
OBAMA1=  - replace
ABBA1w  - not replace
4ABBA1  - not replace
ABBA11  - not replace
e  OBAMA1  - replace  (remark between e to OBAMA1 I have space)
OBAMA1 p   - replace   (remark between OBAMA1 to p I have space)
?OBAMA1    - replace
_OBAMA1_   - replace