Using Git - setup SSH server

People starts to have more than 1 computer to play with. At my case, I have two PCs and 1 laptop and 1 tablet. I use one PC for work and the other PC for private matter and 1 laptop for work and private in mobile. I like to go to a cafe and work at there with my laptop. I see lots of people come to cafe with their laptop. Nowaday, most of popular cafe has power socket at their table or nearby wall. And of course WIFI.

This convenience isn't that convenient when it comes to move around files between PC and laptop. As a software developer, I need to be able to share source code between these computers. Sometimes those files are for work or private or public source code.

I can put all the files in some server and try to download and modify and upload. Or the server can be a source server. At this case, you need to have a server with a fixed IP for this purpose. This asks for money most of the case.

There are another way. You can use a Git. Git is a distributed version control. With Git, you can write code with any of your computer and share it between computer easily.

Roughly speaking, each computer has it's own source repository. After you write code, you will 'commit' it to the local repository which is keeps the changes in it's own computer. Then you will 'push' the committed change to a global repository which can reside in any of your computer. This global repository is where all the changes resides made by all the computer. This repository doesn't have to be on the web. It can be one of your computer. Then you can use another PC or laptop to 'pull' the changes from the global repository. Then makes changes and 'commit' and then 'push'

The distributed part of Git comes handy when you want to see the changed history. The local repository also has all the changed history what global repository has. When you 'push' the changes, all the committed part comes up to the global repository. And then when you 'pull', the local repository gets history of all the changes made by different computer through global repository.

The global repository should be accessible in every computer you have. One way to achieve this is to run a SSH server. This SSH is a gateway that allows other computer to access the computer. Other computer can read/write files in the global repository through SSH server.

SSH server asks a public key for each user. It can be generated using puttygen like below screen shot. You will send the saved public key to the SSH server administrator but keeps the private key in private. Server administrator knows your name and it's public key. And later, when you try to access the server with your name, the SSH server will ask for matched private key to let you in.

Then as SSH Server administrator, you should register you as an user. In here, refer below screen shot with Bitvise SSH Server. You will add an user in the account and then add pulic key you generated using puttygen.

Now when you use Git, you need to use the matched private key to log in the SSH server. Refer below screen shot using TortoiseGit. You can select your private key to log on specific SSH server. In here, I used my computer as SSH server so 'localhost'

After successful log-in, the tortoise git will execute commands of Git which resides at git installer folder e.g. "C:\Program Files (x86)\Git\libexec\git-core". You need to put this path at the environmental variable PATH. Otherwise, the SSH server will just terminate just after executing any git command. e.g. cmd.exe /c git-upload-pack "F:\depo\my_repo.git" - in this case if git-upload-pack is not in path, the cmd.exe just returns without any error.