KSH (1)                       January 1988                       KSH (1)







NAME  

        ksh - Bourne / Korn Shell (Public Domain) 



SYNOPSIS  

        pkshq [p-stq] [p-cq pcommandq] [pfileq [pargument ...q]] 



INTRODUCTION  

        This  document  only  summarizes  the  System V, release 2 shell

        features.  All of the System V features except  for  "restricted

        mode" and  the  CDPATH and MAIL* variables are implemented.  See

        also the BUGS section.  



        Features of the Korn shell are described in more detail.  Only a 

        subset of the Korn shell features are currently implemented.  



DESCRIPTION  



        Command syntax  



        The ``#'' character begins a one-line comment, unless the  ``#''

        occurs inside  a  word.  The tokens ``;'', ``|'', ``&'', ``;;'',

        ``||'', ``&&'', ``('', and ``)'' stand by themselves.  A pwordq is 

        a sequence of any other  non-whitespace  characters,  which  may

        also  contain  quoted strings (quote character are ``º'', ``"'',

        ```'', or a matching ``${ }'' or ``$( )'' pair).  A pnameq  is  an

        unquoted word  made up of letters, digits, or ``_''.  Any number

        of whitespace characters (space and tab) may separate words  and

        tokens.  



        In the  following syntax, { ... }?  indicates an optional thing,

        { ... }* indicates zero or more  repetitions,  {  ...  |  ...  }

        indicates alternatives.  



        statement:  

                p(q list p)q 

                p{q list p;q p}q 

                pforq name { pinq { word }* }?  pdoq list p;q pdoneq 

                pwhileq | puntilq } list p;q pdoq list p;q pdoneq 

                pifq  list  p;q  pthenq  list p;q { pelifq list p;q pthenq list p;q }* {

                pelseq list p;q }?pfiq 

                pcaseq name pinq { p(q word { p|q word } p)q list p;;q }* pesacq 

                pfunctionq name p{q list p;q p}q 

                0me p() {q list p;q p}q 

                ptimeq pipe 

                The opening parenthesis  of  the  pattern  is  optional.

                Redirection  may  occur  at  the  beginning  or end of a

                statement.  



        command:  

                name=word }* { word }* 

                Redirection may occur anywhere in a command.  



        list:  





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                ond 

                ond p;q list 

                ond p&q list 



        cond:  

                ipe 

                ipe p&&q cond 

                ipe p||q cond 



        pipe:  

                tatement { p|q statement }* 



        Alias expansion  



        Alias expansion occurs when the first word of a statement  is  a

        defined   alias,   except  when  that  alias  is  already  being

        expanded.  It also occurs after the expansion of an alias  whose

        definition ends with a space.  



        Shell variables  



        The following standard special variables exist: p!q, p#q, p$q, p-q, p?q.  



        CDPATH  

                Not yet implemented.  



        ENV  

                If  this  variable is set at start-up (after any profile

                files are executed), the expanded value is used as shell 

                start-up file.  It typically contains function and alias 

                definitions.  



        FCEDIT  

                The editor used by the pfcq command.  



        IFS  

                pInternal field separatorq, used during  substitution  and

                the preadq command.  



        HOME  

                The default directory for the pcdq command.  



        MAIL MAILCHECK MAILPATH  

                Not yet implemented.  



        PATH  

                The search path for executable commands and p.q'd files.  



        PS1 PS2  

                pPS1q  is  the  primary  prompt  for  interactive  shells.

                Dollar substitution is performed, and p!q is replaced with 

                the command number (see pfcq).  



        PWD OLDPWD  





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KSH (1)                       January 1988                       KSH (1)





                The current and previous working directories.  



        SECONDS  

                The number of seconds since the shell was started.  



        Substitution  



        In addition to the System Vr2 substitutions, the  following  are

        available.  



        $(command)  

                Like `command`, but no escapes are recognized.  



        $(<file)  

                Equivalent to $(cat file), but without forking.  



        ${#var}  

                The  length of the string value of pvarq, or the number of

                arguments if pvarq is p*q or p@q.  



        ${var#pattern} ${var##pattern}  

                If ppatternq matches the beginning of the  value  of  pvarq,

                the   matched   text  is  deleted  from  the  result  of

                substitution.  A single p#q results in the shortest match, 

                two p#q's results in the longest match.  



        ${var%pattern} ${var%%pattern}  

                Like p#q substition, but deleting  from  the  end  of  the

                value.  



        Expressions  



        Expressions  can  be  used  with  the  pletq  command,  as numeric

        arguments to the ptestq command, and as the value of an assignment 

        to an integer variable.  



        Expression may contain alpha-numeric  variable  identifiers  and

        integer  constants  and  may  be  combined  with  the  following

        operators.  [list them] 



        Command execution  



        After evaluation of keyword assignments and arguments, the  type

        of command  is  determined.    A  command  may  execute  a shell

        function, a shell built-in, or an executable file.  



        Any keyword assignments are then performed according to the type 

        of command.  In function calls  assignments  are  local  to  the

        function.   Assignments  in  built-in  commands  marked with a »

        persist, otherwise  they  are   temporary.      Assignments   in

        executable  commands  are  exported to the sub-process executing

        the command.  



        There are several built-in commands.  





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KSH (1)                       January 1988                       KSH (1)





        :  

                Only expansion and assignment are performed.    This  is

                the default if a command has no arguments.  



        . pfileq  

                Execute the  commands in pfileq without forking.  The file

                is searched  in  the  directories  of  $PATH.    Passing

                arguments is not implemented.  



        alias [pnamep=pvaluep ...]q  

                Without  arguments,  paliasq  lists  all aliases and their

                values.  For any name without  a  value,  its  value  is

                listed.   Any  name  with  a value defines an alias, see

                "Alias Expansion" above.  Korn's tracked aliases are not 

                implemented,  but  System  V  command  hashing  is  (see

                "hash").  



        break [plevelsq]  



        builtin pcommand arg ...q  

                pCommandq is executed as a built-in command.  



        cd [ppathq]  

                Set the  working directory to ppathq.  If ppathq is missing,

                the home directory ($HOME) is used.  If ppathq is  p-q,  the

                previous working  directory is used.  The PWD and OLDPWD

                variables are reset.  The System V two argument form  is

                not implemented.  



        continue [plevelsq]  



        echo ...  

                pEchoq is replaced with the alias echo='print' in the Korn 

                shell.  



        eval pcommand ...q  



        exec pcommand arg ...q  

                The executable  command is executed without forking.  If

                no  arguments  are  given,   any   IO   redirection   is

                permanent.  



        exit [pstatusq]  



        fc [p-lq] [p-nq] [pfirstq [plastq]]  

                A simple  subset  of  Korn's ``fix command''.  pFirstq and

                plastq select commands.    Commands  can  be  selected  by

                history  number,  or  a string specifing the most recent

                command starting with that string.  The p-lq option  lists

                the  command  on  stdout,  and  p-nq  inhibits the default

                command numbers.  Without p-lq, the selected commands  can

                be  edited  by  the p$FCEDITq editor, then executed by the

                shell.  







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        pfc -sq [poldp=pnewq] [pcommandq]  

                Re-execute the selected command (the previous command by 

                default) after performing the optional  substitution  of

                poldq with  pnewq.    This  non-standard  command is usually

                accessed with the predefined alias r="fc -s".  



        getopts  

                See the attached manual page.  



        hash [p-rq] [pname ...q]  

                Without  arguments,  any   hashed   executable   command

                pathnames are  listed.    The  p-rq flag causes all hashed

                commands to be removed.  Each pnameq is searched as if  it

                where  a  command name and added to the hash table if it

                is an executable command.  



        kill [p-psignalq] pprocessq ...  

                Send a signal (TERM by default) to  the  named  process.

                The  signal  may  be specified as a number or a mnemonic

                from <signal.h> with the SIG prefix removed.  



        let [pexpression ...q]  

                Each expression is evaluated, see  "Expressions"  above.

                A  zero  status  is  returned  if  the  last  expression

                evaluates to a  non-zero  value,  otherwise  a  non-zero

                status is returned.  



        pprintq [p-nreupnq] [pargument ...q]  

                pPrintq  prints  its  arguments  on  the  standard output,

                separated by spaces, and terminated with a newline.  The 

                p-nq option eliminates the newline.  



         

                By default, certain C escapes  are  translated.    These

                include  \b, \f, \n, \r, \t, \v, and \### (# is an octal

                digit).  \c is  equivalent  to  the  p-nq  option.    This

                expansion  may be inhibitted with the p-rq option, and may

                be re-enabled with the addition of the p-eq option.  



        read [p-rupnq] pname ...q  

                The first variable name may be of the form pnamep?ppromptq.  



        readonly [pname ...q]  



        return [pstatusq]  

***nroff: unrecognized command .ta 5n 10n 30n



        set [pñqp[a-z]q] [pñoq pkeywordq] ...  

                Set (p-q) or clear (p+q) a shell option: 

                -a llexport ll new  variable  are  created  with  export

                attribute 

                -e \rrexit \xit on non-zero status [incorrect] 

***nroff: no register match