INCOMPATIBLITIES BETWEEN ksh93s- and Solaris /usr/bin/ksh

Of these incompatibilities, the more serious are: 
#1, #4, #5, #8, #9, #10, #13, and possibly #6.

1) In Solaris ksh, in both POSIX-style functions, declared as "func()" 
   and in non-POSIX-style functions, declared as "function func",
   variables can be declared local to that function and all functions
   it calls using the typeset special command, e.g., "typeset var".

   In ksh93, local variables only exist for non-POSIX-style 
   (function func) functions.  In addition, the scope of such 
   local variables defined in non-POSIX functions does not include
   functions called by the current function.  

   In ksh93, in POSIX-style functions (func()),
   variables declared with "typeset var" remain global in scope, 
   and are shared between the calling program and the function.

2) In Solaris ksh, "alias -x" lists the exported aliases.  In ksh93, 
   alias -x exits 0 and outputs nothing.  However in Solaris ksh, exported
   aliases do not work any differently than non-exported aliases.

3) In Solaris ksh, a dollar sign ($') followed by a single quote
   is interpreted literally.  In ksh93, you must escape the dollar
   sign to get the previous behavior.  Similarly, the dollar
   sign ($") preceding a double quote in Solaris ksh must be escaped.
   In ksh93, a $"..." string indicates a string to be translated
   for locales other than C or POSIX.

   Example:
   In Solaris ksh:           In ksh93:
   % echo $'foo'             % echo $'foo'
   $foo                      foo
   % echo $"foo"             % echo $"foo"
   $foo                      foo
   % echo \$'foo'            % echo \$'foo'
   $foo                      $foo
   % echo \$"foo"            % echo \$"foo"
   $foo                      $foo

4) In Solaris ksh, the exit status of a command that terminated because
   it received a signal is 128+<signal #>.  In ksh93, it is 256+<signal #>.
   Users should therefore not be relying on specific exit values,
   other than 0 for success or non-zero otherwise.

5) New built-ins in ksh93.

   ksh93 will include several built-ins which are not built-ins in Solaris ksh,
   and, if executed without a pathname prefix, may be run in place of the 
   corresponding Solaris /usr/bin binaries on the path:

   printf
   sleep

   and these built-ins, which are executed if the corresponding /bin executable
   is found on the path before any other:

   cat
   chown
   head
   mkdir
   rmdir
   tee
   uniq
   wc

   Three known incompatibilities exist in the printf, mkdir, and uniq
   built-ins ksh93, which are based upon POSIX requirements. 
   They are considered bugs, and it is expected that AT&T will
   fix these shortly before or after ksh93 integrates into Solaris.
   See builtin.bugs file for details.

6) Some built-ins don't allow options to be passed in any order as they
   did previously.  For example, in Solaris ksh, "typeset -i8 foo" and
   "typeset -8i foo" work identically to declare the variable foo to
   be a base 8 integer.  In ksh93, "typeset -i8 foo" declares foo to
   be a base 8 integer; "typeset -8i foo" declares foo to be an integer
   with the default base 10

7) The ENV variable in ksh93 is now evaluated for arithmetic expansions 
   $((<arithmetic value>)) and command substitution `<command>`
   In Solaris ksh, it is not.  Previous uses of ` and $( as
   literal values in the ENV variable must be escaped with \.
   This won't be an issue for scripts, which do not execute the 
   file pointed to by ENV.  No problems are anticipated for this case.

8) The ERRNO variable has been dropped in ksh93.

9) In ksh93, pattern matching following a redirection symbol works only
   in interactive shell, not in scripts.  For example, in a script
   executed by Solaris ksh, "echo hi >> foo*" will write to a file
   with a name matching the pattern foo* (starting with the string "foo").
   The same script executed by ksh93 will write to a file literally
   named "foo*".
   
10) In ksh93, the original arguments ($1, $2, $3, etc.) to a script
    are restored after a dot script (. <script> <arg1> <arg2> ...)
    is executed.  In Solaris ksh, the original arguments are cleared
    and replaced by any dot script arguments.

11) In ksh93, tracked aliases are only listed with "alias -t", not
    with "alias" alone.  Solaris ksh lists tracked aliases with both
    "alias" and "alias -t".

12) "kill -l" in Solaris ksh lists all the signal names on a single line
    "kill -l" in ksh93 lists each signal name on a separate line.

13) In arithmetic expansions, e.g., $((<arithmetic expr>)),
    Solaris /usr/bin/ksh will interpret numbers starting with 0 (and not
    starting with 0x or 0X) as decimal, not octal.
    For example: $((010)) is a decimal 10, not an 8.
    In /usr/xpg4/bin/sh and ksh93, $((010)) is interpreted as an octal,
    so it is 8.
    This behavior is the one difference between Solaris /usr/bin/ksh 
    and /usr/xpg4/bin/sh.

    ksh93 additionally differs from the standard Solaris ksh (/usr/xpg4/bin/sh)
    in one other way with respect to this feature, in that, although ksh93 
    recognizes octal *constants* in an arithmetic expansion, it does not 
    interpret *variables* containing numbers starting with 0, as octal
    in an arithmetic expansion.

    That is:

    a=010
    $(($a)) or $((a)) in ksh93 is a decimal 10
    $(($a)) or $((a)) in /usr/xpg4/bin/sh is an octal number, so it is 8
    For UNIX03 standards conformance, the above needs to be interpreted 
    as an octal.

14) In ksh93, the behavior of Ctrl-T in emacs mode is slightly different
    than in Solaris ksh.  In ksh93, in emacs mode, Ctrl-T transposes
    the current and one previous character and moves the cursor
    to the next character.  In Solaris ksh, in emacs mode, Ctrl-T 
    transposes the current and *next* character and moves
    the cursor position over one (to the old current character).
    This is feature is only available for interactive korn shell. 
   
15) In Solaris ksh, if /usr/ucb/echo is found first on the path,
    the built-in echo command will try to emulate /usr/ucb/echo:
    it supports the -n option to eliminate the newline at the
    end of the string, and it will NOT understand the backslash escapes,
    such as \t, \n, \a, etc.
    ksh93 built-in echo does not try to emulate /usr/ucb/echo.

16) In emacs mode, Ctrl-V no longer prints the shell version number.
    Instead, Ctrl-V is now a general escape character, which allows
    one to enter any character using Ctrl-V<character>.
 
17) In ksh93, for all interactive shells, if there exists an
    /etc/ksh.kshrc file, it will be executed before the file named by 
    the ENV environment variable ($HOME/.kshrc, by default).
    Solaris ksh does not execute /etc/ksh.kshrc.