use strict;
my $str = 'cat "food" | c:\\Program Files\\nodejs\\node app.exe
c:\\Program Files\\nodejs\\node.exe
cat "c:\\Program Files\\nodejs\\node.exe" | pipe | c:\\apps and stuff\\node.exe';
my $regex = qr/\\((\w+\s+)+\w+)\\/p;
my $subst = '\\\\"$1"\\\\';
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