I am doing a file search and replace for occurrences of specific words in perl. I\'m not usually much of a perl or regex user. I have searched for other regex questions here
You could try:
s/([^0-9a-z_])([0-9a-z_]+)([^0-9a-z_])/$1$2_tastic$3/gi
Basically, a non-word character, then a set of word characters, followed by a non-word character. The $1,$2,$3 represent the captured groups, and you replace $2 with $2_suffix.
Hope that helps, not a perl guy buy pretty regex-savvy. Note that the above will fail if the word is the very first or very last thing in a string. Not sure if perl regexen allow the syntax, but if so, fixing the first/last issue could be done with:
s/(^|[^0-9a-z_])([0-9a-z_]+)([^0-9a-z_]|$)/$1$2_tastic$3/gi
Using ^ and $ to match beginning/end of string.