Sed failed to match non whitespace characters with character class

Question

I want to extract filter rules configured in /etc/lvm/lvm.conf, like filter = [ \"r|/dev/sda|\" ]. I want sed to return \"r|/dev

Answer 1

Alternatively easier and shorter than [^[:space:]] you can do with \S+ without using brackets []

\S means non whitespace char

echo ' filter = [ "r|/dev/sda|" ] ' | sed -r 's:^\s*filter\s*=\s*\[\s*(\S+)\s*\]:\1:g'

https://ideone.com/PxDX1Q