CSCI 330 THE UNIX SYSTEM Shell Startup and

CSCI 330 THE UNIX SYSTEM Shell Startup and Variables

UNIX COMMAND INTERPRETERS CSCI 330 - The UNIX System 2

LOGIN SEQUENCE establish connection run terminal emulation check userid and password setup environment start command interpreter: shell CSCI 330 - The UNIX System startup settings useful and helpful defaults exit settings 3

SHELL STARTUP SETTINGS terminal settings set path to find executables define custom prompt define command aliases customize common behavior: CSCI 330 - The UNIX System file name completion file overwrite behavior 4

VARIABLES variable is a location in memory where values can be stored 2 types of variables CSCI 330 - The UNIX System environment valid for complete login session upper case by convention shell valid for each shell invocation lower case to display value % echo $variable 5

PREDEFINED ENVIRONMENT VARIABLES Meaning HOME The full pathname of your home directory PATH A List of directories to search for commands MAIL The full pathname of your mailbox USER Your user id SHELL The full pathname of your login shell TERM The type of your terminal PWD Current work directory EDITOR Default editor DISPLAY GUI location “printenv” displays all environment variables CSCI 330 - The UNIX System Name 6