BASH file test operators

Here is a summary of BASH file test operators: 
The general form of a file test operation is -operator "filename"

   
Operator
   
Returns true if
  
   
-e
   
File exist
  
   
-f
   
It is a regular file
  
   
-d
   
File is not zero size
  
   
-s
File has a size greater than zero
  
   
-b
   
File is a block device
  
   
-c
   
File is a character device
  
   
-p
   
File is a pipe (FIFO)
  
   
-h
   
File is a symbolic link
  
   
-L
   
File is a symbolic link
  
   
-S
   
File is a socket
  
   
-t
File (descriptor) is associated with a terminal device
  
   
-r
File has read permissions (for current user)
  
   
-w
   
File has write permissions (for current user)
  
   
-x
   
File has execute permissions (for current user)
  
   
-g
set-group-id (sgid) flag is set on file or directory
  
   
-u
   
set-user-id (suid) flag is set on file
  
   
-k
   
sticky bit is set
  
   
-O
   
File is owned by the effective user id
  
   
-G
   
File is owned by the effective group id
  
   
-N
   
File modified since it was last read
f1 -nt f2
   
File f1 is newer than file f2
  
   
f1 -ot f2
   
File f1 is older than file f2
  
   
f1 -ef f2
   
Files f1 and f2 are hard links to the same file
  
   
!
   
"NOT" - returns true if condition is absent

Execute man bash for more information