Linux shell export command details

Function Description: sets or displays environment variables. Syntax: export [-fnp] [variable name] = [variable setting value] Supplementary Note: When executing a program in shell, shell provides a set of environment variables. Export allows you to add, modify, or delete environment variables for subsequent programs. The effect of export is only true for this logon operation. Parameter:-f indicates the function name in [variable name. -N: Delete the specified variable. The variable is not actually deleted, but is not output to the execution environment of subsequent commands. -P: list all environment variables that the shell assigns to the program. Export PATH = "$ PATH:/home/user/bin" added export-p to display the environment variables that the shell assigns to the program.