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       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of
       this interface may differ (consult the corresponding Linux  manual  page  for  details  of
       Linux behavior), or the interface may not be implemented on Linux.


       delta — make a delta (change) to an SCCS file (DEVELOPMENT)


       delta [-nps] [-g list] [-m mrlist] [-r SID] [-y[comment]] file...


       The delta utility shall be used to permanently introduce into the named SCCS files changes
       that were made to the files retrieved by get (called the g-files, or generated files).


       The delta utility shall conform to the Base Definitions volume  of  POSIX.1‐2017,  Section
       12.2,  Utility  Syntax  Guidelines,  except  that  the  -y  option has an optional option-
       argument. This optional option-argument shall not be presented as a separate argument.

       The following options shall be supported:

       -r SID    Uniquely identify which delta is to be made to the SCCS file. The  use  of  this
                 option  shall  be  necessary  only  if  two or more outstanding get commands for
                 editing (get -e) on the same SCCS file were  done  by  the  same  person  (login
                 name).  The  SID  value  specified  with  the  -r  option  can be either the SID
                 specified on the get command line or the SID to be made as reported by  the  get
                 utility; see get.

       -s        Suppress  the  report  to  standard  output of the activity associated with each
                 file.  See the STDOUT section.

       -n        Specify retention of the edited g-file (normally removed at completion of  delta

       -g list   Specify  a  list  (see  get  for the definition of list) of deltas that shall be
                 ignored when the file is accessed at the change  level  (SID)  created  by  this

       -m mrlist Specify  a modification request (MR) number that the application shall supply as
                 the reason for creating the new delta. This shall be used if the SCCS  file  has
                 the v flag set; see admin.

                 If  -m is not used and '-' is not specified as a file argument, and the standard
                 input is a terminal, the prompt described in the STDOUT section shall be written
                 to  standard  output before the standard input is read; if the standard input is
                 not a terminal, no prompt shall be issued.

                 MRs in a list shall be separated by  <blank>  characters  or  escaped  <newline>
                 characters.  An  unescaped  <newline>  shall  terminate  the MR list. The escape
                 character is <backslash>.

                 If the v flag has a value, it shall be taken to be the name of a  program  which
                 validates  the  correctness  of  the  MR  numbers.  If a non-zero exit status is
                 returned from  the  MR  number  validation  program,  the  delta  utility  shall
                 terminate. (It is assumed that the MR numbers were not all valid.)

                 Describe  the  reason  for  making  the delta. The comment shall be an arbitrary
                 group of lines that would meet the definition of a  text  file.  Implementations
                 shall  support  comments from zero to 512 bytes and may support longer values. A
                 null string (specified as either -y, -y"", or in response  to  a  prompt  for  a
                 comment) shall be considered a valid comment.

                 If  -y  is  not  specified  and '-' is not specified as a file argument, and the
                 standard input is a terminal, the prompt described in the STDOUT  section  shall
                 be written to standard output before the standard input is read; if the standard
                 input is not a terminal, no prompt shall be issued. An unescaped <newline> shall
                 terminate the comment text. The escape character is <backslash>.

                 The -y option shall be required if the file operand is specified as '-'.

       -p        Write  (to standard output) the SCCS file differences before and after the delta
                 is applied in diff format; see diff.


       The following operand shall be supported:

       file      A pathname of an existing SCCS file or a directory. If file is a directory,  the
                 delta  utility  shall behave as though each file in the directory were specified
                 as a named file, except that non-SCCS files (last component of the pathname does
                 not begin with s.)  and unreadable files shall be silently ignored.

                 If  exactly one file operand appears, and it is '-', the standard input shall be
                 read; each line of the standard input shall be taken to be the name of  an  SCCS
                 file  to  be  processed.  Non-SCCS  files and unreadable files shall be silently


       The standard input shall be a text file used only in the following cases:

        *  To read an mrlist or a comment (see the -m and -y options).

        *  A file operand shall be specified as '-'.  In this case, the -y option must be used to
           specify  the comment, and if the SCCS file has the v flag set, the -m option must also
           be used to specify the MR list.


       Input files shall be text files whose data is to be included in the  SCCS  files.  If  the
       first character of any line of an input file is <SOH> in the POSIX locale, the results are
       unspecified. If this file contains more than 99999 lines, the number of lines recorded  in
       the header for this file shall be 99999 for this delta.


       The following environment variables shall affect the execution of delta:

       LANG      Provide a default value for the internationalization variables that are unset or
                 null.  (See  the  Base  Definitions  volume  of   POSIX.1‐2017,   Section   8.2,
                 Internationalization   Variables  for  the  precedence  of  internationalization
                 variables used to determine the values of locale categories.)

       LC_ALL    If set to a non-empty string  value,  override  the  values  of  all  the  other
                 internationalization variables.

       LC_CTYPE  Determine  the  locale for the interpretation of sequences of bytes of text data
                 as characters (for example, single-byte as opposed to multi-byte  characters  in
                 arguments and input files).

                 Determine  the  locale  that should be used to affect the format and contents of
                 diagnostic messages written to standard error, and informative messages  written
                 to standard output.

       NLSPATH   Determine the location of message catalogs for the processing of LC_MESSAGES.

       TZ        Determine  the timezone in which the time and date are written in the SCCS file.
                 If the TZ variable is unset or NULL, an unspecified system default  timezone  is


       If  SIGINT is caught, temporary files shall be cleaned up and delta shall exit with a non-
       zero exit code. The standard action shall be taken for all other signals; see Section 1.4,
       Utility Description Defaults.


       The standard output shall be used only for the following messages in the POSIX locale:

        *  Prompts (see the -m and -y options) in the following formats:

               "MRs? "

               "comments? "

           The MR prompt, if written, shall always precede the comments prompt.

        *  A  report  of  each  file's  activities  (unless  the  -s  option is specified) in the
           following format:

               "%s\n%d inserted\n%d deleted\n%d unchanged\n", <New SID>,
                   <number of lines inserted>, <number of lines deleted>,
                   <number of lines unchanged>


       The standard error shall be used only for diagnostic messages.


       Any SCCS files updated shall be files of an unspecified format.


   System Date and Time
       When a delta is added to an SCCS file, the system date and time shall be recorded for  the
       new delta. If a get is performed using an SCCS file with a date recorded apparently in the
       future, the behavior is unspecified.


       The following exit values shall be returned:

        0    Successful completion.

       >0    An error occurred.



       The following sections are informative.


       Problems can arise if the system date and  time  have  been  modified  (for  example,  put
       forward and then back again, or unsynchronized clocks across a network) and can also arise
       when different values of the TZ environment variable are used.

       Problems of a similar nature can also arise for the operation of the  get  utility,  which
       records the date and time in the file body.








       Section 1.4, Utility Description Defaults, admin, diff, get, prs, rmdel

       The  Base  Definitions  volume  of POSIX.1‐2017, Chapter 8, Environment Variables, Section
       12.2, Utility Syntax Guidelines


       Portions of this text are reprinted and  reproduced  in  electronic  form  from  IEEE  Std
       1003.1-2017,  Standard  for  Information Technology -- Portable Operating System Interface
       (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C)  2018  by
       the  Institute  of  Electrical  and Electronics Engineers, Inc and The Open Group.  In the
       event of any discrepancy between this version and the original IEEE  and  The  Open  Group
       Standard,  the  original  IEEE  and  The  Open Group Standard is the referee document. The
       original Standard can be obtained online at .

       Any typographical or formatting errors that appear in this page are most  likely  to  have
       been  introduced  during  the conversion of the source files to man page format. To report
       such errors, see .