Assuming you can get the lines into an array, grep is your friend:

use strict;
use warnings;
use Data::Dumper qw/Dumper/;
my @lines = (<DATA>);
@lines = grep {/type\s=/} @lines;
print Dumper \@lines;

__DATA__
amis150hx/logic/scl/amis150hxapra/current/amis150hxapra_bc_1.65v_m40c.
+scl 35:    -100mA < i_max < 100mA,
amis150hx/logic/scl/amis150hxapra/current/amis150hxapra_bc_1.65v_m40c.
+scl 36:    -1.10v < vdiode_vss < -0.20v,
amis150hx/logic/scl/amis150hxapra/current/amis150hxapra_bc_1.65v_m40c.
+scl 31:    type = digital_bidir,
amis150hx/logic/scl/amis150hxapra/current/amis150hxapra_bc_1.65v_m40c.
+scl 38:     0.2v < vd < 1.2v,
amis150hx/logic/scl/amis150hxapra/current/amis150hxapra_bc_1.65v_m40c.
+scl 42:    iol = 16mA,
amis150hx/logic/scl/amis150hxapra/current/amis150hxapra_bc_1.65v_m40c.
+scl 43:    ioh = -16mA;
amis150hx/logic/scl/amis150hxapra/current/amis150hxapra_bc_1.65v_m40c.
+scl 45:IOFCXVCVCXVE12S
amis150hx/logic/scl/amis150hxapra/current/amis150hxapra_bc_1.65v_m40c.
+scl 46:    type = digital_bidir,
[download]

Gives:

$VAR1 = [
          'amis150hx/logic/scl/amis150hxapra/current/amis150hxapra_bc_
+1.65v_m40c.scl 31:    type = digital_bidir,
',
          'amis150hx/logic/scl/amis150hxapra/current/amis150hxapra_bc_
+1.65v_m40c.scl 46:    type = digital_bidir,
'
        ];
[download]

Alternately, you can process your file line by line, capturing only lines that match the simple regex I used in the grep block. HTH.