# Detect NAME=Value in shell script.
#
my $findShellVar = qr/\b([-A-Z0-9_]+)=\"(.*?)\"{1}?/sgc;

# Detect embedded use of vars: NAME="text $VAR"
#
my $embeddedVar = qr/$\{?([-_[:alnum:]]+)\}?/gs;

# For each line of the shell script, find shell variable
# assignments, substituting the assigned value for any use
# of other variables, and store result in hash.
#
while my $line ( <EBUILD> ) {
    if ( $line =~ /$findShellVar/ ) {
        my ( $k, $v ) = ( $1, $2 );
        $v =~ s/$embeddedVar/$vars{$1}/;
        $vars{$k} = $v;
    }
}