Linux & environment variables

1. Introduction

1. Linux’s environment variables stored in variable PATH, so can use echo $PATH to check

2. Linux’s environment variables separate by :

   PATH=$PATH:<PATH 1>:<PATH 2>:<PATH 3>:------:<PATH N>

2. searching

1. search all PATH value

   export

2. check PATH environment variable

   echo $PATH

3. listing all set environemnt variables

   set

4. in the home folder

   ctrl h find all Hidden files (name begin with .)

   open .bashrc and edit

5. open .bashrc by command

   vim ~/.bashrc

3. adding

1. temporarily adding

   export NAME=VALUE

   examples:

   export JAVA_HOME=/opt/openjdk11

   export PATH=/usr/local/nginx/sbin/:$PATH

   adding /usr/local/nginx/sbin/ index adding to the environment temporarily

2. current user adding permanent

   vim ~/.bashrc

   add export PATH="/usr/local/nginx/sbin/:$PATH" at the end of the file

   source ~/.bashrc

3. all users adding permanent

   vim /etc/profile

   add export PATH="/usr/local/nginx/sbin/:$PATH" at the end of the file

   source  /etc/profile

4. deleting

unset VARIABLE_NAME

examples:

unset JAVA_HOME