Shell Study Note

5.1

Printenv	View Global variables
Bash	New shell
Set	Global variables and localvariables
Export Test	Local→global, so it can be accessed in both Subshell andmain shell.
unset test	Delete a variable, no $ needed.
path= $PATH: ...	Append PATH, no" "needed, export needed to make it global.
. BASHRC	Define own aliases

User-definedvariables is lower-cased; While SYS variables is upper.

test=testing;

Remember there isno BLANK;

Bash:new a shell,the subshell have no $test variable for it are user-defined; So it iswith the Subshell.

To fix this, we can "export test", and NO $ needed.

When unset a globalvar, it is influent the Subshell who execute this cmd.

Shell Study Note