/proc/mounts to JSON with perlcore only

mounts2json.pl

#!/usr/bin/perl
use strict;
use warnings;
use diagnostics;

use JSON::PP;

my @only = qw(ext4);

my @mounts = ();

for (`cat /proc/mounts`) {
  my ($fsname, $fstype, $fsmodes) = m/\S+ (\S+) (\S+) (\S+)/;

  next unless grep { $fstype =~ $_ } @only;

  push @mounts, {
    '#FSNAME'  => $fsname,
    '#FSTYPE'  => $fstype,
    '#FSMODES' => $fsmodes,
  };
}

print JSON::PP->new->pretty->canonical->encode({ mounts => \@mounts });

perl mounts2json.pl

{ "mounts" : [
   {
      "#FSMODES" : "rw,relatime,errors=remount-ro",
      "#FSNAME" : "/",
      "#FSTYPE" : "ext4"
   },
   {
     "#FSMODES" : "rw",
     "#FSNAME" : "/data",
     "#FSTYPE" : "ext4"
   }
]}