SSH - Black Magic

Remote port forwarding - Public connections to my laptop on any network:
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ssh -R ${remote}:${local} remote

Initiated by the remote machine.
Example:
1.) Run this on your Mac

ssh -R *:2020:localhost:22  -i awskey.pem ec2-user@ec2-xx-xx-xxx-xxx.us-west-2.compute.amazonaws.com

2.) Then on AWS machine to access your Mac:

ssh macuser@localhost -p 2020

Local port forwarding:
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ssh -L ${local}:${remote} remote

Initiated by the local machine.

3.) Dynamic port forwarding, SOCKS 5 proxy using '-D' flag


Original link:
https://vimeo.com/54505525

Finding the exact binary library containing the symbols in a directory of binaries

Sometimes while compiling a program you run into an issue of missing symbols; e.g.

Undefined symbols for architecture x86_64:

  "cv::MSER::create(int, int, int, double, double, int, double, double, int)", referenced from:

      getBlackAndWhiteImage(cv::Mat, int, double, double, double, std::__1::vector<std::__1::vector<cv::Point_<int>, std::__1::allocator<cv::Point_<int> > >, std::__1::allocator<std::__1::vector<cv::Point_<int>, std::__1::allocator<cv::Point_<int> > > > >&, std::__1::vector<cv::Rect_<int>, std::__1::allocator<cv::Rect_<int> > >&) in showimg-53afc0.o

ld: symbol(s) not found for architecture x86_64

Now you need to find the exact binary file in lets say a directory, this command can help you with it:

find /usr/local/lib/libopencv_* | awk '{ print "echo "$1"; nm "$1" | grep -i MSER" }' | sh