Environment variablesEnvironment variable is a storage location where is name and value. They often affect the way programs behave.
printenv command – Print all or part of environment.
env command – Print all exported environment or run a program in a modified environment.
set command – Print the name and value of each shell variable.
printenv without arguments print all variables.
printenv name_of_variable - print only this variable
[root@rifle ~]# printenv HISTSIZE
The same result you can get using the echo command. The variable name has to be used with $ .
[root@rifle ~]# echo $HISTSIZE
!Some information about used variables can be found in man pages of the command.
! Environment variables names are case sensitive.
Preserve variables from session to session
Save them to your personal ~/.bash_profile file