method
test
test(command, file1, file2=nil)
public
CommandProcessor#test(command, file1, file2) CommandProcessor#[command, file1, file2]
command: char or String or Symbol
file1: String
file2: String(optional)
return: Boolean
same as:
test() (when command is char or length 1 string or symbol)
FileTest.command (others)
example:
sh[?e, "foo"]
sh[:e, "foo"]
sh["e", "foo"]
sh[:exists?, "foo"]
sh["exists?", "foo"]

