How to access environment variables from the front-end

There is a very simple way to to that: Step one: Go to the root folder of your application and create a text file called .env. Step two: Create your custom variables in the new file. Create React App(CRA) enforces the prefix REACT_APP on every custom variable. Please note that variables without the prefix are … Read more

Difference between shell and environment variables

Citing this source, Standard UNIX variables are split into two categories, environment variables and shell variables. In broad terms, shell variables apply only to the current instance of the shell and are used to set short-term working conditions; environment variables have a farther reaching significance, and those set at login are valid for the duration … Read more

Referencing Environment Variables in web.xml

You can use Ant-style variable substitution in any of the tomcat xml config files, such as: <servlet-mapping> <servlet-name>mvc-dispatcher</servlet-name> <url-pattern>${foo}</url-pattern> </servlet-mapping> Where foo is a Java System Property (sysprop). You can’t use OS Environment Variables (envvars) directly, I think… To use envvars, you can put set “CATALINA_OPTS=-DsomeJavaSysProp=%SOME_OS_ENVVAR%” in bin/setenv.bat (or similarly in bin/ for *nix). You … Read more

Can envsubst not do in-place substitution?

Here is the solution that I use: originalfile=”file.txt” tmpfile=$(mktemp) cp –attributes-only –preserve $originalfile $tmpfile cat $originalfile | envsubst > $tmpfile && mv $tmpfile $originalfile Be careful with other solutions that do not use a temporary file. Pipes are asynchronous, so the file will occasionally be read after it has already been truncated.

PyCharm not updating with environment variables

When any process get created it inherit the environment variables from it’s parent process (the O.S. itself in your case). if you change the environment variables at the parent level, the child process is not aware of it. PyCharm allows you to change the environment variables from the Run\Debug Configuration window. Run > Edit Configurations … Read more

Environment variable assignment in Docker Compose – colon way

The documentation itself says both methods are working: You can use either an array or a dictionary. Now let’s forgive Docker for failing to use the proper terminology (an array is actually a sequence in YAML, a dictionary is a mapping) and have a look from the YAML perspective: A mapping is part of the … Read more