> /^[[:space:]]*\(iface\|auto\|mapping\|source\|allow-\) ! s/^/#NetworkManager#//;
I mean
/^[[:space:]]*\(iface\|auto\|mapping\|source\|allow-\)/ ! s/^/#NetworkManager#//;
of course ;)
> /^[[:space: ]]*\(iface\ |auto\| mapping\ |source\ |allow- \) ! s/^/#NetworkMan ager#// ;
I mean
/^[[:space: ]]*\(iface\ |auto\| mapping\ |source\ |allow- \)/ ! s/^/#NetworkMan ager#// ;
of course ;)