Museum

Home

Lab Overview

Retrotechnology Articles

⇒ Online Manual

Media Vault

Software Library

Restoration Projects

Artifacts Sought

     Name
          delta - make a delta (change) to an SCCS file

     Syntax
          delta [-rSID] [-s] [-n] [-glist] [-m[mrlist]] [-y[comment]]
          [-p] files

     Description
          The delta command is used to permanently introduce into the
          named SCCS file changes that were made to the file retrieved
          by get(CP) (called the g-file, or generated file).

          The delta command makes a delta to each named SCCS file.  If
          a directory is named, delta behaves as though each file in
          the directory were specified as a named file, except that
          non-SCCS files (last component of the path name does not
          begin with s.) and unreadable files are silently ignored.
          If a name of - is given, the standard input is read (see
          Warnings); each line of the standard input is taken to be
          the name of an SCCS file to be processed.

          The delta command may issue prompts on the standard output
          depending upon certain keyletters specified and flags (see
          admin(CP)) that may be present in the SCCS file (see -m and
          -y keyletters below).

          Keyletter arguments apply independently to each named file.

               -rSID          Uniquely identifies which delta is to be
                              made to the SCCS file.  The use of this
                              keyletter is necessary only if two or
                              more outstanding gets for editing (get
                              -e) on the same SCCS file were done by
                              the same person (login name).  The SID
                              value specified with the -r keyletter
                              can be either the SID specified on the
                              get command line or the SID to be made
                              as reported by the get command (see
                              get(CP)).  A diagnostic results if the
                              specified SID is ambiguous or if a
                              required SID is omitted on the command
                              line.

               -s             Suppresses the issue, on the standard
                              output, of the created delta's SID, as
                              well as the number of lines inserted,
                              deleted, and unchanged in the SCCS file.

               -n             Specifies retention of the edited g-file
                              (normally removed at completion of delta
                              processing).

               -glist         a list (see get(CP) for the definition
                              of list) of deltas which are to be
                              ignored when the file is accessed at the
                              change level (SID) created by this
                              delta.

               -m[mrlist]     If the SCCS file has the v flag set (see
                              admin(CP)), then a Modification Request
                              (MR) number must be supplied as the
                              reason for creating the new delta.

                              If -m is not used and the standard input
                              is a terminal, the prompt MRs? is issued
                              on the standard output before the
                              standard input is read; if the standard
                              input is not a terminal, no prompt is
                              issued.  The MRs? prompt always precedes
                              the comments? prompt (see -y keyletter).

                              MRs in a list are separated by blanks
                              and/or tab characters.  An unescaped
                              new-line character terminates the MR
                              list.

                              Note that if the v flag has a value (see
                              admin(CP)), it is taken to be the name
                              of a program (or shell procedure) which
                              will validate the correctness of the MR
                              numbers.  If a non-zero exit status is
                              returned from the MR number validation
                              program, delta terminates.  (It is
                              assumed that the MR numbers were not all
                              valid.)

               -y[comment]    Arbitrary text used to describe the
                              reason for making the delta.  A null
                              string is considered a valid comment.

                              If -y is not specified and the standard
                              input is a terminal, the prompt
                              comments? is issued on the standard
                              output before the standard input is
                              read; if the standard input is not a
                              terminal, no prompt is issued.  An
                              unescaped new-line character terminates
                              the comment text.

               -p             Causes delta to print (on the standard
                              output) the SCCS file differences before
                              and after the delta is applied in a
                              diff(C) format.

     Files
          g-file           Existed before the execution of delta;
                           removed after completion of delta.
          p-file           Existed before the execution of delta; may
                           exist after completion of delta.
          q-file           Created during the execution of delta;
                           removed after completion of delta.
          x-file           Created during the execution of delta;
                           renamed to SCCS file after completion of
                           delta.
          z-file           Created during the execution of delta;
                           removed during the execution of delta.
          d-file           Created during the execution of delta;
                           removed after completion of delta.
          /usr/bin/bdiff   Program to compute differences between the
                           ``gotten'' file and the g-file.

     See Also
          admin(CP), cdc(CP), get(CP), prs(CP), rmdel(CP),
          sccsfile(F), bdiff(C)

     Warnings
          Lines beginning with an SOH ASCII character (binary 001)
          cannot be placed in the SCCS file unless the SOH is escaped.
          This character has special meaning to SCCS (see sccsfile(F))
          and will cause an error.

          A get of many SCCS files, followed by a delta of those
          files, should be avoided when the get generates a large
          amount of data.  Instead, multiple get/delta sequences
          should be used.

          If the standard input (-) is specified on the delta command
          line, the -m (if necessary) and -y keyletters must also be
          present.  Omission of these keyletters causes an error to
          occur.

          Comments are limited to text strings of at most 512
          characters.

     Standards Conformance
          delta is conformant with:
          AT&T SVID Issue 2, Select Code 307-127;
          and The X/Open Portability Guide II of January 1987.

                                                (printed 6/18/89)






Typewritten Software • bear@typewritten.org • Edmonds, WA 98026