# Configure Multiple Git Accounts on a Single Computer Sometimes we need to work with multiple repositories or groups of repositories that use different git accounts on the same computer. Here, a git account refers to an account created on online version control system (VCS) platforms, such as Github, Bitbucket, Gitlab, etc. One way to accomplish this is to change the account information used by git whenever we switch repositories. But, keep changing this information is a tedious and error-prone task. We want to configure git such that, whenever we change repositories, it automatically picks up the correct information. Let's see how to do that... ## Scenario In this article, we will consider the following scenario: We have 3 git accounts (Steps to get SSH User and Hostname are given below): 1. First Account ```bash # Account 1 Name = John Doe Email = johndoe.codeready@gmail.com GitLab Username = @johndoe.codeready SSH User = git SSH Hostname = gitlab.com ``` 2. Second Account ```bash # Account 2 Name = Jack Smith Email = jacksmith.codeready@gmail.com Github Username = jack-codeready SSH User = git SSH Hostname = github.com ``` 3. Third Account (Default Account) ```bash # Account 3 Name = John Doe Email = johndoe.codeready@gmail.com Github Username = john-codeready SSH User = git SSH Hostname = github.com ``` To get the value of SSH `User` and `Hostname` for any account, do the following: 1. Login to the account. 2. Go to any repository (Create one if there is no repository). 3. Click on the **Code** button for the GitHub repository or the **Clone** button for the GitLab repository. 4. Select **SSH as** the clone method. 5. Copy the SSH URL. It will be in the format of `{User}@{Hostname}:{Organization}/{Repository Name}` . 6. And you have the value of SSH `User` and `Hostname` for that account. The following screenshot is taken from Github. Here, SSH User is `git` and Hostname is `github.com`. ![Image showing SSH User and Hostname for a github repository](https://cdn.hashnode.com/res/hashnode/image/upload/v1671640732537/qD2lI3Lfj.png align="center") The following screenshot is taken from GitLab. Here, SSH User is `git` and Hostname is `gitlab.com`. ![Image showing SSH User and Hostname for a GitLab repository](https://cdn.hashnode.com/res/hashnode/image/upload/v1671726443218/1b7852af-9a32-46c9-b77a-291b6546fa1e.png align="center") In most cases, the SSH User will be `git`, but it is better to follow the steps to get both the `User` and the `Hostname`. We have 2 directories `Projects` and `Development` in home(`~`) directory. Our goal is that for any repository inside `Projects` directory git should use `Account1` and for any repository inside `Development` git should use `Account2`. For all other repositories, which are not in any of these directories, it should use `Account3`. We want to use `SSH` for authentication and authorization and want to sign the commits using the correct GPG keys. ## git-config FILES By default, git reads configuration options from some pre-defined files. One of them is `~/.gitconfig`. In this file, we can define some configuration options and can include other configuration files. These files contain information related to the git username, email, GPG sign key, etc. GPG keys are used to sign the commits while committing changes to any branch. Git uses another file which is `~/.ssh/config` to make an SSH connection to GitHub (or any other online VCS platform) to authorize the current user. This is used while cloning the repository, pulling/fetching changes from the online repository, pushing changes to the online repository, or any other git operations that include communication with GitHub. ## Creating config files ### Create a common / default config file Create a file `.gitconfig` in the home directory. Update the `~/.gitconfig` file with the following content: ```apache # ~/.gitconfig ######### Common and Default Configuration for Git ######### # Congiguration for default user (Account 3, in this scenario) # to be used by git [user] # Personal name of the git user name = John Doe # Email Address of the git user email = johndoe.codeready@gmail.com # Signing key to sign the commits by this user # For now, it is empty # Later, we will generate it and will update this file signingKey = # Configuration related to Commits [commit] # Since, gpgsign = true, git will always sign the commits # Otherwise, whenever we want to sign the commits, we need # to use "-S" flag while commiting. Ex - # git commit -S -m "Commit Message" # And, often we forget to include this flag and that leads # to a lot of extra work gpgsign = true # This condition check if the current git directory # is inside "~/Projects/" path [includeIf "gitdir:~/Projects/"] # In that case, we also use the configurations specified # in "~/.gitconfig.projects" file. # In "~/.gitconfig.projects" file, we can add new config values # or can updated the existing config values path = ~/.gitconfig.projects [includeIf "gitdir:~/Development/"] path = ~/.gitconfig.development ``` In the above file: * We have specified the name, email, and signing key for the default user. * We have specified that we want every commit to be signed. * We instructed git to read configurations from `~/.gitconfig.projects` also if the current repository is inside `~/Projects` directory. * We instructed git to read configurations from `~/.gitconfig.development` also if the current repository is inside `~/Development` directory. ### Create config files for different accounts Let's create 2 files (`~/.gitconfig.projects` and `~/.gitconfig.development` ) for `Account1` and `Account2`, respectively. ```apache # ~/.gitconfig.projects ######### Configuration for Account1 ######### # Congiguration for Account1 to be used by git when we are inside # "~/Projects/" repository [user] # Personal name of the git user name = John Doe # Email Address of the git user email = johndoe.codeready@gmail.com # Signing key to sign the commits by this user # For now, it is empty # Later, we will generate it and will update this file signingKey = ``` ```apache # ~/.gitconfig.development ######### Configuration for Account2 ######### # Congiguration for Account2 to be used by git when we are inside # "~/Development/" repository [user] # Personal name of the git user name = Jack Smith # Email Address of the git user email = jacksmith.codeready@gmail.com # Signing key to sign the commits by this user # For now, it is empty # Later, we will generate it and will update this file signingKey = ``` For all 3 accounts, we will generate signing keys later. ### Create SSH config file Create a file `config` inside `~/.ssh/` directory, if it is not there. And put the following content there: ```apache # SSH Configuration for Account1 # John Doe's GitLab Account Host account1 User git Hostname bitbucket.org IdentityFile # Location of identity file for account1 (will update later) AddKeysToAgent yes # SSH Configuration for Account2 # Jack Smith's GitHub Account Host account2 User git Hostname github.com IdentityFile # Location of identity file for account2 (will update later) AddKeysToAgent yes # SSH Configuration for Account3 (Default Account) # John Doe's GitHub Account Host account3 User git Hostname github.com IdentityFile # Location of identity file for account3 (will update later) AddKeysToAgent yes ``` We are almost done with the configuration files. We need to generate SSH keys and GPG keys for each account and need to update the config files. Let's do that now. ## Generate and Configure SSH Keys For each account, follow these steps to generate, upload and use the SSH Keys. ### Generate SSH Keys Generate SSH Key using the following steps: 1. Open Terminal (Mac/Linux) or Git Bash (Windows). 2. Run the following command with the correct email address: ```bash ssh-keygen -t ed25519 -C "johndoe.codeready@gmail.com" ``` 3. If you are asked to enter the file name to save the key, use a different filename for each account (You can include GitHub/GitLab username in the filename to make them unique for each account). In the following code snippet, I am using `/c/Users/himan/.ssh/id_ed25519_johndoe.codeready` as the filename for `Account 1`. Here `johndoe.codeready` is the GitLab username of `Account 1`. ```bash Generating public/private ed25519 key pair. Enter file in which to save the key (/c/Users/himan/.ssh/id_ed25519): /c/Users/himan/.ssh/id_ed25519_johndoe.codeready ``` 1. When asked, enter a passphrase for the ssh key. (You will be asked to enter the same passphrase twice). **You must remember the passphrase**. 2. If we look at the files inside `~/.ssh` directory, we see 2 files for one ssh key - One without any extension and one with `.pub` extension. The file without any extension is **Private Key** and the file with the extension `.pub` is **Public Key**. Don't share your *Private Key* with anyone. We will upload the *Public Key to GitH*ub or GitLab. ### Upload Public SSH Key to GitHub / GitLab Follow these steps to upload the public ssh key (one with `.pub` extension) to GitHub or GitLab: 1. Copy the content from *Public SSH Key*. The SSH key file has `.pub` extension. 2. If the account is related to Github, go to [https://github.com/settings/keys](https://github.com/settings/keys) and click on the **New SSH Key** button. If the account is related to GitLab, go to [https://gitlab.com/-/profile/keys](https://gitlab.com/-/profile/keys). 3. Give some Title/Label to the key. 4. If asked for the **Key Type**, select *Authentication Key*. 5. Paste the copied content in the **Key** textbox. 6. Click on **Add Key** button. ### Configure the ssh-config file to use the ssh-key Now, add the path of the **Private SSH Key** file for the value of `IdentityFile` variable in the `~/.ssh/config` file for the correct account. After following all the 3 steps for all accounts, we created SSH keys for each account, uploaded public SSH keys to the corresponding online VCS account and we have added the location of private SSH keys inside `~/.ssh/config` file. The `~/.ssh/config` should look like this: ```bash # SSH Configuration for Account1 # John Doe's GitLab Account Host account1 # ssh -T account1 User git Hostname gitlab.com IdentityFile ~/.ssh/id_ed25519_johndoe.codeready AddKeysToAgent yes # SSH Configuration for Account2 # Jack Smith's Github Account Host account2 # ssh -T account2 User git Hostname github.com IdentityFile ~/.ssh/id_ed25519_jack-codeready-github AddKeysToAgent yes # SSH Configuration for Account3 (Default Account) # John Doe's Github Account Host account3 # ssh -T account3 User git Hostname github.com IdentityFile ~/.ssh/id_ed25519_john-codeready-github AddKeysToAgent yes ``` Now, let's test if the SSH configuration is working or not. Run the following command to authenticate `Account 1` : ```bash ssh -T account1 ``` If it is the first time connecting to this account, it will ask for confirmation, type `yes` and press Enter. When asked for a passphrase, enter the passphrase created while generating the corresponding ssh keys. Then, it will show a message that you are authenticated using ssh. ![](https://cdn.hashnode.com/res/hashnode/image/upload/v1671727217199/894b3c64-d69a-4212-8eda-8b60a4d6b0a9.png align="center") Thus, we can connect to the git accounts using the correct ssh keys. It's time to configure GPG keys so our commits are signed correctly. Let's do that now. ## Generate and Configure GPG Keys For each account, do the following to generate, upload and configure the GPG key. ### Generate GPG Key 1. Open Terminal / Git Bash. 2. Run the following command: ```bash gpg --full-generate-key ``` 3. At the prompt, specify the kind of key you want. Type `1` and press `Enter` to accept the default. 4. When asked for the length of the key, specify `4096`. 5. Enter the length of time for which the key should be valid. If you don't want the key to expire, type `0` and press `Enter`. 6. When asked for confirmation, specify `y`. 7. When asked, enter your real name. 8. Then enter the email address related to the account. 9. Then you need to add a comment to the GPG key. Add something specific to the account so that later you can recall the purpose of the key. For instance, I have specified `John Doe - GitLab Account` as a comment for `Account 1`. 10. Type a secure passphrase (and re-type it). 11. Run the following command to list the GPG keys: ```bash gpg --list-secret-keys --keyid-format=long ``` The output will be similar to the following (You may have more than one key). ```bash sec rsa4096/75BDED420C522BEB 2022-12-22 [SC] AE815B28610907D3A31E19BD75BDED420C522BEB uid [ultimate] John Doe (John Doe - GitLab Account) ssb rsa4096/08310F3B00DB38D1 2022-12-22 [E] ``` 12. Copy the long form of the GPG key id that you want to use (The comment related to the key can be useful to recognize the key). In the above example, the GPG key Id is `75BDED420C522BEB`. 13. Run the following command to get the Public GPG key for the above id (Replace the id with your id): ```bash gpg --armor --export 75BDED420C522BEB # Prints the GPG key ID, in ASCII armor format ``` The output will be similar to the following: ```bash -----BEGIN PGP PUBLIC KEY BLOCK----- mQINBGOkiMwBEACzHZDQUmibFy3/jBNBROBHG5CridNUorgW8dBzbNyw9hyV5FYL # Some more stuff =Wci4 -----END PGP PUBLIC KEY BLOCK----- ``` Copy the whole output, which is your Public GPG key. ### Upload Public GPG Key to Account For the GitHub account, go to [https://github.com/settings/keys](https://github.com/settings/keys) and click on the **New GPG Key** button. For the GitLab account, go to https://gitlab.com/-/profile/gpg\_keys. Paste the public GPG key in the text box and click on the **Add Key** button. ### Update git config file with Id of GPG key Paste the id of the GPG key (`75BDED420C522BEB` in this case) as the value of the `signingKey` variable in the appropriate git config file, which we created earlier. In this case, since this is for `Account 1`. So, I will put it in the `~/.gitconfig.projects` file. After the above steps, below are the 3 updated config files: `~/.gitconfig` ```bash # ~/.gitconfig ######### Common and Default Configuration for Git ######### # Congiguration for default user (Account 3, in this scenario) # to be used by git [user] # Personal name of the git user name = John Doe # Email Address of the git user email = johndoe.codeready@gmail.com # Signing key to sign the commits by this user signingKey = FF650CD14C619C34 # Configuration related to Commits [commit] # Since, gpgsign = true, git will always sign the commits # Otherwise, whenever we want to sign the commits, we need # to use "-S" flag while commiting. Ex - # git commit -S -m "Commit Message" # And, often we forget to include this flag and that leads # to a lot of extra work gpgsign = true # This condition check if the current git directory # is inside "~/Projects/" path [includeIf "gitdir:~/Projects/"] # In that case, we also use the configurations specified # in "~/.gitconfig.projects" file. # In "~/.gitconfig.projects" file, we can add new config values # or can updated the existing config values path = ~/.gitconfig.projects [includeIf "gitdir:~/Development/"] path = ~/.gitconfig.development ``` `~/.gitconfig.projects` ```bash # ~/.gitconfig.projects ######### Configuration for Account1 ######### # Congiguration for Account1 to be used by git when we are inside # "~/Projects/" repository [user] # Personal name of the git user name = John Doe # Email Address of the git user email = johndoe.codeready@gmail.com # Signing key to sign the commits by this user signingKey = 75BDED420C522BEB ``` `~/.gitconfig.development` ```bash # ~/.gitconfig.development ######### Configuration for Account2 ######### # Congiguration for Account2 to be used by git when we are inside # "~/Development/" repository [user] # Personal name of the git user name = Jack Smith # Email Address of the git user email = jacksmith.codeready@gmail.com # Signing key to sign the commits by this user signingKey = C8A49A252EF556F7 ``` ## How to use it? If you create any git repository inside `Projects` directory, Git will automatically pick the configurations for `Account 1` and so on. You can also clone repositories for `Account1` inside `Projects` repository using the below command: ```bash git clone account1:johndoe.codeready/hello-gitlab.git ``` And whenever you commit any changes, Git will ask for the passphrase for the GPG key and it will sign the commits with the correct GPG key based on which directory you are in. That's it for this article. It is a long one, but it can save you a lot of time later if you work on multiple projects involving different accounts on a single machine. You don't need to change configurations for Git whenever you change the project/directory.