Limiting SED to the first 10 characters of a line

Question

I'm running sed as a part of a shell script to clean up bind logs for insertion into a database.

One of the sed commands is the following:

sed -i 's/-/:/g' $DPath/named.query.log

This turns out to be problematic as it disrupts any resource requests that also include a dash (I'm using : as a delimiter for an awk statement further down).

My question is how do I limit the sed command above to only the first ten characters of the line? I haven't seen a specific switch that does this, and I'm nowhere near good enough with RegEx to even start on developing one that works. I can't just use regex to match the preceding numbers because it's possible that the pattern could be part of a resource request. Heck, I can't even use pattern matching for ####-##-## because, again, it could be part of the resource.

Any ideas are much appreciated.

Answer 1

It's [almost always] simpler with awk:

awk '{target=substr($0,1,10); gsub(/-/,":",target); print target substr($0,11)}' file