Yan Burtovoy web dev notes

$() means: "first evaluate this, and then evaluate the rest of the line". Ex : echo $(pwd)/myFile.txt will be interpreted as echo /my/path/myFile.txt On the other hand ${} expands a variable. Ex: MY_VAR=toto echo ${MY_VAR}/myFile.txt will be interpreted as echo toto/myFile.txt sudo -i is the way to go if you don't want to be typing a password every 10 mins while doing modifications in your system (or other systems), and you don't want to modify any system files. It will switch you to root using your sudo user password, when you close the console or type exit you are back to your normal user. src:  https://askubuntu.com/questions/147241/execute-sudo-without-password

*********** choose B1S for free usage during 12 month. src: https://azure.microsoft.com/en-us/free/free-account-faq/ 750 hours of Azure B1S General Purpose Virtual Machines for Linux 12 months disk: ssd premium the problem is disk IO max limit. 16.9 MB/s solvation: increase swap. by the way - it's completely disabled by default! sudo dd if=/dev/zero of=/swapspace bs=1M count=2000 sudo mkswap /swapspace sudo swapon /swapspace watch -n 1 cat /proc/swaps grep SwapTotal /proc/meminfo src: https://askubuntu.com/questions/566745/allocate-swap-after-ubuntu-14-04-lts-installation https://bogdancornianu.com/change-swap-size-in-ubuntu/ https://www.tecmint.com/commands-to-monitor-swap-space-usage-in-linux/ clear: apt autoclean xbcnbnm от headers after it can be installed firefox: sudo apt-get install firefox before continue: sudo apt-get update CAUTIONS: !!!!!!!!!RDP:  firefox freeze in a ~10 minutes and cause os to stuck. *********** RDP: src: https://www.youtube.c