Is sxxyy equivalent to s/xx/yy/?

Yes. You can also use s<xx><yy> & s{xx}{yy] & s(xx)(yy) & any combination thereof.

it does not work as written. I am using Perl 5.8.8.

I think \K is a 5.10+ism. It was released 3 1/2 years ago and has many very useful additions, especially where regex are concerned. You should seriously consider upgrading.

As a poor substitute, you could use this for 5.8:

@a = 'a'..'u';;

$s = join ',', @a;;

$s =~ s[((?:,[^,]+){6}),][$1\n]g;;

print $s;;
a,b,c,d,e,f,g
h,i,j,k,l,m,n
o,p,q,r,s,t,u
[download]