Friday, 3 June 2016

Enter RSA passphrase once when using Git bash

When using Git bash it can become annoying if you have to enter your RSA passphrase every time you perform a remote operation. You can easily prevent this by using ssh-agent and running it when Git bash first runs.

Open a text editor and create a new text file. Paste the following bash script into the file:

#! /bin/bash 
eval `ssh-agent -s` 
ssh-add ~/.ssh/*_rsa

Note that my RSA key file is called id_rsa and is stored in the .ssh folder in my user’s home directory.

Save the file created above as .bashrc in your user’s home directory. Now, when you start a Git bash session you should be prompted for your passphrase. This will remain active for the duration of the session and you won’t have to enter it again.


See Saving an SSH key when using Git for info on generating the RSA key file.

Thursday, 2 June 2016

Git recipies

This post is a quick aide-mémoire for basic command-line Git operations. Well worth reading is the Git Getting Started documentation.

Clone a remote repository for the first time

To get started crack open Git bash and go to your source folder. You can then clone a remote repository into a new folder simply by running the following command:

someuser@mymachine MINGW64 ~
$ cd c:

someuser@mymachine MINGW64 /c
$ cd Source/

someuser@mymachine MINGW64 /c/Source
$ git clone git@some:repo/Some.Project.git
Cloning into 'Some.Project'...
Enter passphrase for key '/c/Users/someuser/.ssh/id_rsa':
remote: Counting objects: 1402, done.
remote: Compressing objects: 100% (1311/1311), done.
emote: Total 1402 (delta 1018), reused 87 (delta 59)Receiving objects:  87% (1220/1402), 580.00 KiB | 1.08 MiB/s

Receiving objects: 100% (1402/1402), 1.15 MiB | 1.08 MiB/s, done.
Resolving deltas: 100% (1018/1018), done.
Checking connectivity... done.

someuser@mymachine MINGW64 /c/Source

See the Git - git-clone Documentation.

List branches

The following command lists all local and remote branches:

someuser@mymachine MINGW64 /c/Source/Some.Project (master)
$ git branch -a
* master
  remotes/origin/HEAD -> origin/master

See Git – git-branch Documentation.

To see remote branches only use the –r switch. For local only use the –l branch.

someuser@mymachine MINGW64 /c/Source/Some.Project (master)
$ git branch -r
  origin/HEAD -> origin/master

someuser@mymachine MINGW64 /c/Source/Some.Project (master)
$ git branch -l
* master                                                           

Getting more information about the remote repository

someuser@mymachine MINGW64 /c/Source/Some.Project (master)
$ git remote -v
origin  git@some:repo/Some.Project.git (fetch)
origin  git@some:repo/Some.Project.git (push)

someuser@mymachine MINGW64 /c/Source/Some.Project (master)
$ git remote show

someuser@mymachine MINGW64 /c/Source/Some.Project (master)
$ git remote show origin
Enter passphrase for key '/c/Users/someuser/.ssh/id_rsa':
* remote origin
  Fetch URL: git@some:repo/Some.Project.git
  Push  URL: git@some:repo/Some.Project.git
  HEAD branch: master
  Remote branches:
    develop                          tracked
    feature/IntialLoggingIntegration tracked
    master                           tracked
  Local branch configured for 'git pull':
    master merges with remote master
  Local ref configured for 'git push':
    master pushes to master (up to date)

Checkout a remote branch

To switch to a new remote branch and check its status:

someuser@mymachine MINGW64 /c/Source/Some.Project (master)
$ git checkout develop
Branch develop set up to track remote branch develop from origin.
Switched to a new branch 'develop'

someuser@mymachine MINGW64 /c/Source/Some.Project (develop)
$ git status
On branch develop
Your branch is up-to-date with 'origin/develop'.
nothing to commit, working directory clean

Create a new branch

This example shows how to create a feature branch off develop:

someuser@mymachine MINGW64 /c/Source/Some.Project (develop)
$ git checkout -b feature/test develop
Switched to a new branch 'feature/test'

See the Git - git-checkout Documentation. Also see the Git Branching - Basic Branching and Merging.

Delete a branch

The following example shows how to delete a branch. Note you can’t be on the branch you’re deleting.

someuser@mymachine MINGW64 /c/Source/Some.Project (develop)
$ git branch -D feature/test
Deleted branch feature/test (was 2647fba).

See the Git - git-branch Documentation. Also see the Git Branching - Basic Branching and Merging.

Revert changes to a file

You can see which files have been modified locally using the “git status” command and then undo the changes with “git checkout”:

someuser@mymachine MINGW64 /c/Source/Some.Project (develop)
$ git status
On branch develop
Your branch is up-to-date with 'origin/develop'.
Changes not staged for commit:
  (use "git add ..." to update what will be committed)
  (use "git checkout -- ..." to discard changes in working directory)

        modified:   src/Some.Project/App.config
        modified:   src/Some.Other.Project/config/App.config

no changes added to commit (use "git add" and/or "git commit -a")

someuser@mymachine MINGW64 /c/Source/Some.Project (develop)
$ git checkout -- src/Some.Project/App.config

Merge the develop branch into a feature branch

If you are using Git Flow and you are working on a feature branch you might want to merge develop into your feature branch from time to time to minimise conficts once your feature is complete. The basic commands to use would be:

someuser@mymachine MINGW64 /c/Source/Some.Project (develop)
$ git checkout feature/test
Switched to branch 'feature/test'
Your branch is up-to-date with 'origin/feature/test'.

someuser@mymachine MINGW64 /c/Source/Some.Project (feature/test)
$ git merge develop

See the Git – git-merge Documentation.

Checking to see what might be committed (dry-run)

An easy one - how can you see what will be committed without actually doing so? Like this:

someuser@mymachine MINGW64 /c/Source/Some.Project (develop)
$ git commit --dry-run

See the Git – git-commit Documentation.

Delete a local branch

someuser@mymachine MINGW64 /c/Source/Some.Project (develop)
$ git branch -d SomeBranchName
Deleted branch SomeBranchName (was 76e05d9).

See the Git – git-branch Documentation.

Move changes to a new branch

If you’ve made changed to a branch but want to move them to a new branch and commit them there do the following (substituting ‘NewBranchNameHere’ with the desired branch name):

someuser@mymachine MINGW64 /c/Source/Some.Project (develop)
$ git checkout -b NewBranchNameHere

Then do git add and git commit as usual.