-d
Directory test, if
-f
File test, if
&
Writable/variable test, if
-e
Exists file, if
[[]]
Bracket format to contain regex
-eq
Equality
-ne
Inequality
-gt
Greater
-lt
Lesser
-ge
Greater than or equal
-le
Lesser than or equal
$() or -
Command expression. For use in [for i in ] -esque statements.
seq
Step through numbers in range. Default 1. Number in between and is a defined increment.
exec
Redirect output from shell to file
Ex: exec > out.log
read
Read input from user applies to var. for command script.