How to remove non-greedy suffix from string in bash?

Question

I would like to remove any suffix from a string starting with the last .svc. . As a example:

abc.svc.cluster.local => abc

abc.svc.svc.cluster.local => abc.svc

abc.txt => abc.txt

abc.svc.xyz.svc.zzz => abc.svc.xyz

svc.xxx => svc.xxx (missing . before svc)

If I was doing this is Go, I would find the last index of substring .svc. and then trim from that index.

How do I do this in bash? Thanks.

Answer 1

Like this:

$ v=abc.svc.svc.cluster.local
$ echo ${v%.svc*}
abc.svc
$ v=abc.svc.cluster.local
$ echo ${v%.svc*}
abc

And, use %% for the greedy behavior:

$ v=abc.svc.svc.cluster.local
$ echo ${v%%.svc*}
abc

---

According to man bash:

• ${parameter%word}
  ${parameter%%word}

  The word is expanded to produce a pattern just as in pathname expansion. If the pattern matches a trailing portion of the expanded value of parameter, then the result of the expansion is the expanded value of parameter with the shortest matching pattern (the % case) or the longest matching pattern (the %% case) deleted. [...]