public/subjects/devops/set-env-vars

set-env-vars

Instructions

Create a script set-env-vars.sh, which will allow you to set the following variables as environment variables and and print only the ones you created:

• MY_MESSAGE which contains the string "Hello World".
• MY_NUM which contains the number 100.
• MY_PI which contains the number 3.142.

Expected output:

$ printenv  # The env variables present are just an example, yours will be different.
SHELL=/bin/bash
TERM=xterm
USER=demouser
MAIL=/var/mail/demouser
PATH=/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games
PWD=/home/demouser
SHLVL=1
HOME=/home/demouser
LOGNAME=demouser
_=/usr/bin/printenv
$ ./set-env-vars.sh
MY_NUM=100
MY_PI=3.142
MY_MESSAGE=Hello World
$

Hints

Setting values to environment variables:

In order to set a value to an existing environment variable, we use an assignment expression. For instance, to set the value of the "LANG" variable to "he_IL.UTF-8", we use the following command:

$ LANG=he_IL.UTF-8

If we use an assignment expression for a variable that doesn't exist, the shell will create a shell variable, which is similar to an environment variable but does not influence the behavior of other applications.

A shell variable can be exported to become an environment variable with the export command. To create the "EDITOR" environment variable and assign the value "nano" to it, you can do:

$ EDITOR=nano
$export EDITOR

echo is not allowed in the exercise! Try to use the command printenv and filter with grep to get only the variables that you created.

You have to use Man or Google to know more about commands flags, in order to solve this exercise! Google and Man will be your friends!