use strict;
my $str = 'net trunk RandomNameTrunk { bandwidth 20000 cfg-mbr-count 2 id 0 interfaces { 2.1 2.2 } lacp enabled
net trunk DifferentNameTrunk { bandwidth 4000 cfg-mbr-count 2 id 0 interfaces { 1.1 1.2 1.3 1.4 } lacp enabled
net trunk trunk#1 { bandwidth 20000 cfg-mbr-count 2 id 0 interfaces { 2.1 2.2 } lacp enabled
net trunk trunk#2 { bandwidth 4000 cfg-mbr-count 2 id 0 interfaces { 1.1 1.2 1.3 1.4 } lacp enabled';
my $regex = qr/^net trunk\s+(\S+)[^{]*{.*{ *([^}]*?) *}.*$/mp;
my $subst = '$1 $2';
my $result = $str =~ s/$regex/$subst/rg;
print "The result of the substitution is' $result\n";
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Perl, please visit: http://perldoc.perl.org/perlre.html