--help display this help and exit

--version
       output version information and exit

-n STRING
       the length of STRING is nonzero

STRING equivalent to -n STRING

-z STRING
       the length of STRING is zero

STRING1 = STRING2
       the strings are equal

-b FILE
       FILE exists and is block special

-c FILE
       FILE exists and is character special

-d FILE
       FILE exists and is a directory

-e FILE
       FILE exists

-f FILE
       FILE exists and is a regular file

-g FILE
       FILE exists and is set-group-ID

-G FILE
       FILE exists and is owned by the effective group ID

-h FILE
       FILE exists and is a symbolic link (same as -L)

-k FILE
       FILE exists and has its sticky bit set

-L FILE
       FILE exists and is a symbolic link (same as -h)

-O FILE
       FILE exists and is owned by the effective user ID

-p FILE
       FILE exists and is a named pipe

-r FILE
       FILE exists and read permission is granted

-s FILE
       FILE exists and has a size greater than zero

-S FILE
       FILE exists and is a socket

-t FD  file descriptor FD is opened on a terminal

-u FILE
       FILE exists and its set-user-ID bit is set

-w FILE
       FILE exists and write permission is granted

-x FILE
       FILE exists and execute (or search) permission is granted