CONDITIONAL EXPRESSIONS

       -a file
              True if file exists.
       -b file
              True if file exists and is a block special file.
       -c file
              True  if  file  exists  and  is a character special
              file.
       -d file
              True if file exists and is a directory.
       -e file
              True if file exists.
       -f file
              True if file exists and is a regular file.
       -g file
              True if file exists and is set-group-id.
       -h file
              True if file exists and is a symbolic link.
       -k file
              True if file exists and its ``sticky'' bit is  set.
       -p file
              True if file exists and is a named pipe (FIFO).
       -r file
              True if file exists and is readable.
       -s file
              True  if  file  exists  and has a size greater than
              zero.
       -t fd  True if file descriptor fd is open and refers to  a
              terminal.
       -u file
              True if file exists and its set-user-id bit is set.
       -w file
              True if file exists and is writable.
       -x file
              True if file exists and is executable.
       -O file
              True if file exists and is owned by  the  effective
              user id.
       -G file
              True  if  file exists and is owned by the effective
              group id.
       -L file
              True if file exists and is a symbolic link.
       -S file
              True if file exists and is a socket.
       -N file
              True if file exists and has been modified since  it
              was last read.
       file1 -nt file2
              True  if  file1 is newer (according to modification
              date) than file2.
       file1 -ot file2
              True if file1 is older than file2.
       file1 -ef file2
              True if file1 and file2 have the  same  device  and
              inode numbers.
       -o optname
              True  if  shell option optname is enabled.  See the
              list of options under the  description  of  the  -o
              option to the set builtin below.
       -z string
              True if the length of string is zero.
       -n string
              True if the length of string is non-zero.
       string1 == string2
              True  if  the  strings are equal.  = may be used in
              place of ==.
       string1 != string2
              True if the strings are not equal.
       string1 < string2
              True if string1 sorts before string2  lexicographi-
              cally in the current locale.
       string1 > string2
              True  if  string1 sorts after string2 lexicographi-
              cally in the current locale.
       arg1 OP arg2
              OP is one of -eq,  -ne,  -lt,  -le,  -gt,  or  -ge.
              These  arithmetic  binary  operators return true if
              arg1 is equal to, not equal  to,  less  than,  less
              than  or equal to, greater than, or greater than or
              equal to arg2, respectively.  Arg1 and arg2 may  be
              positive or negative integers.
	expr1 -a expr2
		logical "AND"
	expr1 -o expr2
		logical "OR"