macOS X

Switching between different installed Java versions in macOS X #

Once you have several java versions installed, you can configure your .bash_profile to have the following lines:

alias j16="export JAVA_HOME=`/usr/libexec/java_home -v 16`;  java -version"
alias j12="export JAVA_HOME=`/usr/libexec/java_home -v 12`;  java -version"
alias j11="export JAVA_HOME=`/usr/libexec/java_home -v 11`;  java -version"
alias j10="export JAVA_HOME=`/usr/libexec/java_home -v 10`;  java -version"
alias j9="export JAVA_HOME=`/usr/libexec/java_home  -v 9`;   java -version"
alias j8="export JAVA_HOME=`/usr/libexec/java_home  -v 1.8`; java -version"
alias j7="export JAVA_HOME=`/usr/libexec/java_home  -v 1.7`; java -version"

Generating self-signed SSL certificates to be used in Nginx #

The same command works on Linux.

openssl req -x509 -nodes -days 36500 -newkey rsa:2048  \ 
  -keyout private-selfsigned.key -out public-selfsigned.crt

Discover the IPs that are being resolved for a domain #

nslookup google.se

Creating a brew PR to upgrade a version #

Let’s take Opera as an example. The Opera’s tap is here.

To upgrade brew casks:

brew bump-cask-pr opera --version 77.0.4054.276

And for regular formulas:

brew bump-formula-pr  ...

Creating permanent aliases #

Create a file like ~/.bash_aliases

cd; touch .bash_aliases

Add alias on it;

echo "myalias=\"ls\"" >> .bash_aliases

Reference the alias in your bash profile by adding the follow lines.

if [ -f ~/.bash_aliases ]; then
. ~/.bash_aliases
else 
  touch .bash_aliases;
  echo alias=myalias >> .bash_aliases;
fi
alias j11='export JAVA_HOME=/Library/Java/JavaVirtualMachines/adoptopenjdk-11.jdk/Contents/Home; java -version'
alias j16='export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk-16.0.2.jdk/Contents/Home; java -version'
alias startDependenciesj11='cd ~/Documents/git/bucket-service-monthly/; j11; ./gradlew startDependencies;'