separate with "-" every 4 characters in long string

[w5000]

hello,

example input lines in a file:

htrfskjfsfhssflk
weoiurweroiljask

desired output:

htrf-skjf-sfhs-sflk
weoi-urwe-roil-jask

thank you in advance for some short awk solution!

 

[w5000]

ok,thank you -- google already found it.

sed 's/..../&-/g;s/-$//'

awk '{for(i=1;i<=length($0);i+=4){printf("%s-",substr($0,i,4))}}'|awk '{sub(/-$/,"")};1'