Consider these important facts:
- Environment variables are all upper case.
- To use their values, precede the name with a
Initializing Your Environment
Linux utilizes Bash as the default shell and when a session started it reads commands from
Environment variables are set in the file
📝 Note: The files
.bashrc are hidden. To list hidden files, type
Know the Environment Variables
Here is a list of some common environment variables:
$HOME- Path of your home directory
$PATH- List of directories where the system checks for programs to run
$LD_LIBRARY_PATH- List of directories where the system checks for shared libraries to load
$HOSTNAME- The name of the host, e.g.
📝 Note: See the values of all your environment variables by typing
env on your terminal.
Working with the Environment Variables
Display the value of an environment variable using
echo $HOME /home/UID
Modify the value of environment variables with
export PATH=$PATH:/home/UID export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/home/UID/custom_lib_directory
Set a value for environment variables:
This command sets the value of the variable called OMP_NUM_THREADS (an OpenMP parameter) to 12.