To show all values of these variables, typeĪn example of a shell variable is the history variable. PATH (the directories the shell should search to find a command)įinding out the current values of these variables.ĮNVIRONMENT variables are set using the setenv command, displayed using the printenv or env commands, and unset using the unsetenv command.PRINTER (the default printer to send print jobs).DISPLAY (the name of the computer screen to display X windows).ARCH (the architecture of the computers processor).HOST (the name of the computer you are using).

HOME (the path name of your home directory).

More examples of environment variables are The value of this is the current operating system you are using. 8.2 Environment VariablesĪn example of an environment variable is the OSTYPE variable. By convention, environment variables have UPPER CASE and shell variables have lower case names. 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 of the session. Standard UNIX variables are split into two categories, environment variables and shell variables. Some are set by the system, others by you, yet others by the shell, or any program that loads another program. Programs look 'in the environment' for particular variables and if they are found will use the values stored.

Variables are a way of passing information from the shell to programs when you run them.

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