Well, let's use a language with better bigint support. Yes, I know about Math::BigInt, but others will tell you about that anyway, so I'll show other solutions. For these, you have to install respective software (dc, bc, ruby) if you don't already have it. 

perl -we '"38"=~/(-?)(\d+)/ and $decimal = ($1?"_":"").$2; `dc -e 2o${
+decimal}p` =~ /(-?[01]+)/ and $binary = $1; print $binary, "\n";'

perl -we '"9007199254740991"=~/(-?\d+)/ and $decimal = $1; `echo obase
+=2\\;${decimal} | bc` =~ /(-?[01]+)/ and $binary = $1; print $binary,
+ "\n";'

perl -we '"9007199254740991"=~/(-?\d+)/ and $decimal = $1; `ruby -e\47
+printf(%[%b],\$*[0])\47 ${decimal}` =~ /(-?[01]+)/ and $binary = $1; 
+print $binary, "\n";'

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In reply to Re^3: decimal to binary conversion need help by ambrus
in thread decimal to binary conversion need help by Anonymous Monk

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