DEV Community: JDeep

Bisect: A severely underrated git command

JDeep — Fri, 27 Aug 2021 16:58:32 +0000

`git bisect`

Ever faced a situation where you made multiple commits to your project only to break a feature which you are sure it worked properly before you went on the commit spree?

How on earth do you even plan to begin debugging the code in such a scenario?

One could go on a brute force approach but wouldn't it be much easier(to debug) if git just tells you which commit messed up your feature?

git bisect does exactly that.

Suppose I have a commit history as shown below:

Lets say my feature worked properly in 29aa243. I want to find which commit between 29aa243 and d3bf6d2 broke my feature.

Before beginning to bisect the commits, lets get a basic understanding of the involved commands

To start bisecting, we run the command :

git bisect start

This would start a bisecting session where you have to test your feature and tell git if it works fine or is still broken.

git bisect good [optional commit] # If the feature works fine
git bisect bad  [optional commit] # If the feature is still broken

This is a simple logic graph of the process:

Now, We have to first initialize which commit is good and which is bad . In this scenario, my d3bf6d2 (current HEAD) is bad and 29aa243 is good. Do this with the help of commands given above

Now test your feature and subsequently go through the logic graph given above(Note: It is very important that you donot begin to commit on the codebase in a Bisecting Session. Since the HEAD remains in a detached state in such session, it would give you a hard time fixing everything later. See the last part of this article on how to exit Bisecting Session).

In the end of all revisions, git will tell which commit broke your feature :]

Now that you have found your guilty commit, its time to reattach your Detached HEAD back to master. Do this to reattach your detached HEAD

git bisect reset

Good luck with debugging that commit 👍. Here are some more sources to learn about git bisect :

https://git-scm.com/docs/git-bisect

https://stackoverflow.com/questions/4713088/how-to-use-git-bisect

Bspwm installation on Ubuntu 20.04 [updated :2021]

JDeep — Wed, 24 Mar 2021 14:12:52 +0000

Note : Donot blindly copy the commands otherwise very bad things will happen.

Step 1 : Install bspwm

either by installing from the debian repository or by building it from source .I will be using the debian repository for installation
Run the following commands. Use sudo if you are not root



apt-get update && apt update
apt install bspwm

You should get a prompt like this :

See carefully that the dependencies like bspwm lemonbar libxcb-ewmh2 sxhkd xdo are automatically installed so you dont have to install these manually. Keep in mind though that if you are building from source , you would need to install these dependencies manually either from debian repository or by building them from source

Step 2 :Configuring bspwm and sxhkd

Now the bspwm file was downloaded into your system and in almost all cases, the files are found in /usr/share/doc/bspwm

In this folder , there are example config files that you can use. Or if you want , you can make your config files from scratch.
I will be using the examples configs to wrap it up faster

From /usr/share/doc/bspwm/examples we will copy the bspwmrc and sxhkdrc to ~/.config directory

First make two directories (bspwm and sxhkd) in your .config folder.

Next copy the bspwmrc and sxhkdrc in /usr/share/doc/bspwm/examples to your .config directory using the following commands



mkdir ~/.config/bspwm && mkdir ~/.config/sxhkd
cp /usr/share/doc/bspwm/examples/bspwmrc ~/.config/bspwm
cp /usr/share/doc/bspwm/examples/sxhkdrc ~/.config/sxhkd

Step 3 : Making executables and firing up bspwm

Normally , the bspwmrc file that you copied just now should be an executable. You can check if its an executable or not from the this SO post or if you have a file manager like vifm or ranger then , placing the cursor on bspwmrc file should highlight it in green colour (which means that its an executable and you can proceed to the next step)

See this:

If its not executable , then make it executable by



chmod +x bspwmrc

Step 4 : Modifying the `.sxhkdrc` so that you can open some apps after logging into bspwm.

If you did the above steps correctly , you should see something like this in your sxhkdrc

Now change the default urxvt terminal to the terminal of your choice. I will set super + Return to my default gnome-terminal.
You can also add your keybindings for opening web browser.

Step 5 : Putting bspwm in your `.xsession` or `.Xsession` or `xsessionrc` or `.xinit` file.

Note 1 : Focus on the or in the heading. That means to do the following steps in only one file not all :-)

Note 2 : Check if you have any the files in the heading in your home directory. In my case I didn't have them so I had to make them.

Making these files are simple. Just touch .xsessionrc .

Edit the file and put the following lines in it :



#!/bin/bash
exec bspwm

Note 3 : I got my bspwm running by adding the above lines in .xsessionrc . It may be possible that in your case you have to add the lines in .xsession or any other file mentioned in the heading.

Step 6 : Making the `xsession` file executable

First cd to your home directory where you have the file you created/modied in Step 5.

Then open the terminal and enter the following :



chmod +x  .xsessionrc

Note : I created a .xsessionrc file. If you have used any other file in Step 5 , then make it executable instead !

Logut and login again and you will be greeted with a black screen.

Use the keybinding you added in Step 4 to open up the terminal and install essentials like polybar , picom etc

Sources:

https://dev.to/l04db4l4nc3r/bspwm-a-bare-bones-window-manager-44di

https://www.maths.cam.ac.uk/computing/linux/X/xsession

https://github.com/baskerville/bspwm/wiki

https://wiki.archlinux.org/index.php/bspwm