I'm using Ubuntu, so i suppose this alias will work on every Debian based distro, but i dont have sure. Anyway, here it goes:
amixer set Capture toggle
If you type it on your bash, you will alternate your microphone on/off switch (toggle). Thats pretty useful if you're working remotely with lots of video/sound channels, for example, you just toggle your mic off and mute all your apps and channels.
Lets turn it into a permanent alias.
For that, open a terminal and type the command below:
echo "alias mic='amixer set Capture toggle'" >> ~/.bashrc && . ~/.bashrc
Now if you type
mic on your terminal it will toggle your microphone and show a status message. So, when you want to mute all apps, or have sure you didnt missed anything, just type mic and turn off your microphone.
Thats all ;)