Findings

Who’s using my macbook camera?

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So the other day I was working away on my Macbook Pro and suddenly, out of the blue, the light next to my camera came on. Now, this is a new macbook so I don’t have my little sliding window sticker that blocks my webcam yet. Even if I did have it, I’d still be equally worried. So I started digging. The only apps I had open at the time were:

  • Firefox
  • BlueJeans (video conferencing software)
  • Intellij IDEA
  • Visual Studio Code
  • iTerm

Basically the Software Engineer’s toolkit.

After a little digging on the Internet, I found a few commands that could help me. I have conveniently combined them all into this single command:

lsof | grep -e "AppleCamera" -e "iSight" -e "VDC"

This gave me the following:

➜  ~ lsof | grep -e "AppleCamera" -e "iSight" -e "VDC"
firefox   1956 mdave  txt       REG                1,5      424176 1152921500312438057 /System/Library/Frameworks/CoreMediaIO.framework/Versions/A/Resources/VDC.plugin/Contents/MacOS/VDC

Hmm so its Firefox? Weird because usually its very good with permissions. Most of my tabs were DuckDuckGo, StackOverflow, Jira, Confluence, Gmail and a few other “trusty” company web pages. This couldn’t be it?

I did some digging around in settings but no luck. Finally, I brought down the hammer and took away the permissions to Camera (and Microphone for safety) from the System Preferences. And viola!

➜  ~ lsof | grep -e "AppleCamera" -e "iSight" -e "VDC"
firefox   1956 mdave  txt       REG                1,5      424176 1152921500312438057 /System/Library/Frameworks/CoreMediaIO.framework/Versions/A/Resources/VDC.plugin/Contents/MacOS/VDC
➜  ~ lsof | grep -e "AppleCamera" -e "iSight" -e "VDC"
➜  ~

No more naughty webcam access! I guess if I need it again, I’ll just give it permissions explicitly through the System Preferences. Or perhaps I can side-install another firefox browser when I need to grant it permissions to view my webcam – the number of websites that I use that need this permission are very small in number and I can live with using a dedicated web browser for it.

Mac command to view last login/wake/sleep/charge times

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The pmset utility on mac is quite useful for viewing system logs. If you type:

you’ll be able to see some cool system logs. However, as a timesaver, here’s a no-bullshit command to view the following times:

  • When mac went into sleep
  • When mac came out of sleep
  • Charge levels
  • Standby times

Enjoy!

Bulk edit filenames using shell

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Unix/linux command to remove specific matching text from all files. In this case, I had a list of tiles that had -defaults.properties suffix. I wanted to rename them all so that they had just .properties suffix instead. For example, if a file was named connection-defaults.properties, I wanted it to be renamed to connection.properties. 

As usual, rather than wasting my time and doing it manually 100 times, I set myself to find an automated way of doing it. And sure enough, I found it!

Here it is:

The above command finds all files that end with -defaults.properties. For each file that match that criteria, we then rename it to a name that has -defaults stripped out. To strip out the name, we use sed command and to rename we use mv command.

Tested on mac running oh-my-zsh.

Documenting project information with Maven

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In most projects I’ve worked on, the project information is captured in some sort of README.md file. While this has its strengths, such as ability to write free form text and embed images, it doesn’t quite fit with the project because when the artifact is produced during the build time, the read me is not checked into the artifact repository along with it. So how do I know who the contributors were for that specific artifact version? How do I know where the project was hosted at the time?

Well, today I learned that maven provides ability to capture some of those attributes and some more! I like this because it means that when the artifact gets checked in (along with its pom.xml) the details about the project are captured for that version, frozen in time.

Great thing about these attibutes is that when you run mvn site they are used in the project information html page that maven produces. Technically, then you can upload this to any statically hosted site location, all versioned up and ready to be explored.

Ok so lets begin exploring these attributes. The first three attributes are the basic ones:

For people working in corporations and companies, the following might be useful, especially when open sourcing the project:

Additionally, the licenses tag can be used to describe some licensing information. How many times have you come across a project that has changed the licensing information half way through versions? This is a life saver (at least legally)!

Some source control information is also useful, however, whats more useful is knowing where to go in order to raise issues. In most companies, people use source control to store code but then use an alternative mechanism like Jira or Trello to mange issues. The scm and issueManagement tags are useful here in clarifying such information:

Developer information on projects is very useful. Companies don’t usually like this because, well, developers are supposed to be expendable, however, in my humble opinion, it is useful to list developers who were working on the project at the time. This way the versions can be tracked, at least to the lead working on it at the time. Use it thusly:

For contributors, people who have worked on the project, although not necessarily part of it exclusively, use:

Lastly, it is useful to capture some information about pipeline that was used to create the project. For this, maven has ciManagement tag:

The above is just a small example of what you can do with these attributes, there are many more sub-attributes that you can explore. Hope this is a good introduction and kicks off some ideas of what you can do with this information.

Finding classes in jar/war files

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Recently I was out looking for classes that were present in my Web Application Archive (WAR) file. Why? Well, I was out combating Jar Hell. As I am allergic to doing things manually, here’s a small command I constructed to help me find classes within jar files:

The above command prints out class file as well as the name of the jar file that class is present in. If you’re looking just for the path where the classes are present, you can just run: