-e、-d、-f、-L、-r、-w、-x、-s、-h、

- e filename True if filename exists
 - d filename True if filename is a directory 
 - f filename True if filename is a regular file
 - L filename True if filename is a symbolic link
 - r filename True if filename readable - true 
 if filename - w filename true if filename is writable 
 - x filename true if filename is executable
 - s filename true if file length is not 0
 - h filename if file is a softlink, is true
filename1 - nt filename2 True if filename1 is newer than filename2.
filename1 - ot filename2 True if filename1 is older than filename2.
- eq is equal to
 - ne is not equal to
 - gt is greater than
 - ge is greater than or equal to
 - lt is less than
 - le is less than or equal to