#! perl -slw
use strict;

while( <DATA> ) {
    print "$1 : ", $2||$3 while m[
        (\w+)               ## the name
        \s+=\s+             ## the =
        (?:                 ## Either
            ' ( [^']+ ) '   ## all the non-quotes between quotes
        |                   ## or
            (.*?)           ## the minimum
        )
        \s{2,}              ## absorb the two or more spaces
    ]gx;
}

=results
P:\test>junk
drsubc : agauss(0, 1, 3)
delm1 : 0 + 0.045u*distm1
delm2 : 0 + 0.07u*distm2
delm3 : 0 + 0.07u*distm3
delm4 : 0 + 0.07u*distm4
delmt : 0 + 0.07u*distmt
delml : 0.16u + 0.43u*distml
delam : 0.32u + 0.86u*distam
dele1 : 0 + 0.25u*diste1
dele2 : 0 + 0.25u*diste2
delma : 0.16u + 0.6u*distma
pmsxt : npmsxt + 12.5u*dpmsxt
tih : 0.35u
capct : 0.50u + 0.13u*xdcapct
capcti : 0.55u + 0.13u*xdcapct
m1t : 0.41u + 0.05u*xdm1t
m1ti : 0.36u + 0.05u*xdm1t
m2t : 0.48u + 0.057u*dm2t
m3t : 0.48u + 0.057u*dm3t
m4t : 0.48u + 0.057u*dm4t
mtt : 0.48u + 0.057u*dmtt
qtt : 0.242u + 0.0202u*dqtt
htt : 0.242u + 0.0202u*dhtt
mlt : 2.0u + 0.2u*dmlt
amt : 4.0u + 0.4u*damt
e1t : 3.0u + 0.5u*de1t
e2t : 4.0u + 0.5u*xde1mat
mat : 4.0u + 0.4u*dmat
m1m2t : 0.35u + 0.05u*dm1m2t
=cut

__DATA__
drsubc  = agauss(0, 1, 3)   delm1   = '0 + 0.045u*distm1'               delm2   = '0 + 0.07u*distm2'        delm3   = '0 + 0.07u*distm3'                delm4   = '0 + 0.07u*distm4'                delmt   = '0 + 0.07u*distmt'                delml   = '0.16u + 0.43u*distml'            delam   = '0.32u + 0.86u*distam'            dele1   = '0 + 0.25u*diste1'                dele2   = '0 + 0.25u*diste2'                delma   = '0.16u + 0.6u*distma'             pmsxt   = 'npmsxt + 12.5u*dpmsxt'           tih     = 0.35u                capct   = '0.50u + 0.13u*xdcapct'           capcti  = '0.55u + 0.13u*xdcapct'           m1t     = '0.41u + 0.05u*xdm1t'    m1ti    = '0.36u + 0.05u*xdm1t'             m2t     = '0.48u + 0.057u*dm2t'             m3t     = '0.48u + 0.057u*dm3t'             m4t     = '0.48u + 0.057u*dm4t'             mtt     = '0.48u + 0.057u*dmtt'             qtt     = '0.242u + 0.0202u*dqtt'           htt     = '0.242u + 0.0202u*dhtt'           mlt     = '2.0u + 0.2u*dmlt'                amt     = '4.0u + 0.4u*damt'                e1t     = '3.0u + 0.5u*de1t'            e2t     = '4.0u + 0.5u*xde1mat'             mat     = '4.0u + 0.4u*dmat'                m1m2t   = '0.35u + 0.05u*dm1m2t'