delta(1)							     delta(1)



NAME
  delta - Saves editing changes in a Source Code Control System (SCCS) file

SYNOPSIS

  delta [-g list] [-m MRlist] [-n] [-p] [-s] [-r SID] [-y][comment] file ...
       | -

  The delta command introduces into the named SCCS file any changes that were
  made to the file version retrieved by an SCCS get -e command.

FLAGS

  -glist
      Specifies a list of SIDs (deltas) that are to be ignored when the get
      command creates the g-file.  After you use this flag, get ignores the
      deltas in this list when it builds the g-file.

  -m[MRlist]
      Specifies a Modification Request (MR) number as the reason for creating
      the new delta.

      If the SCCS file has the v header flag set, then a MR number must be
      provided.	 If you specify -m, the MRs are taken from MRlist.

      If you do not specify the -m flag, delta reads MRs from the standard
      input.  If standard input is a tty, delta prompts you for the MRs.
      delta continues to take input until it reads End-of-File.	 It always
      reads MRs before the comments (see the -y flag).	You can use spaces,
      tab characters, or both to separate MRs in a list.

      If the v header flag has a value, it is interpreted as the name of a
      program that validates the MR numbers.  If delta returns a nonzero exit
      value from the MR validation program, delta assumes some of the MR
      numbers were invalid and stops running.

  -n  Retains the g-file, which is normally removed at completion of delta
      processing.

  -p  Writes to standard output (in the format of the sccsdiff command) the
      SCCS file differences before and after the delta is applied.  (See the
      sccsdiff command for more information.)

  -rSID
      Specifies which delta is to be made to the SCCS file.  You must use
      this flag only if two or more outstanding get -e commands were done on
      the same SCCS file by the same person.  The SID can be either the SID
      specified on the get command line or the SID to be made as reported by
      the get command.	An error results if the specified SID cannot be
      uniquely identified, or if a SID must be specified, but it is not.

  -s  Suppresses the information normally written to standard output on nor-
      mal completion of the delta command.

  -y[comment]
      Specifies text used to describe the reason for making the delta.	A
      null string is considered a valid comment.  If your comment line
      includes special characters or spaces, the line must be enclosed in
      single or double quotes.

      If you do not specify -y, delta reads comments from standard input
      until it reads a blank line or End-of-File.  If input is from the key-
      board, delta prompts for the comments.  If the last character of a line
      is a \ (backslash), it is ignored.  Comments must be no longer than 512
      characters.

DESCRIPTION

  The delta command reads the g-files that correspond to the specified files
  (see the get command) and creates a new delta.

  If you specify a directory in place of file, delta performs the requested
  actions on all SCCS files within that directory (that is, on all files with
  the s. prefix).  If you specify a - (dash) in place of file, delta reads
  standard input and interprets each line as the name of an SCCS file.	When
  delta reads standard input, you must supply the -y flag.  You must also
  supply the -m flag if the v header flag is set.  (For more information on
  header flags, see the admin(1) command.)  delta reads standard input until
  it reaches End-of-File.

  Avoid a get of many SCCS files followed by a delta of those files when the
  get generates a large amount of data.	 Instead, alternate the use of get
  and delta.

  To use the delta command, do the following:

   1.  Use get -e to get an editable version of the file.

   2.  Edit that file.

   3.  Use delta to create a new version of the SCCS file.

  The delta command prompts you for comments.  The comments are for that par-
  ticular delta and appear in the SCCS file header.  The comments are not
  retrieved when you get the delta and do not appear in the text of a
  retrieved file.  Use comments to keep track of why a delta was created.

  To see the comments, use an editor to look at the SCCS file, write the SCCS
  file to the display screen with the cat command, or print selected parts of
  the file to standard output using the prs command. Remember not to change
  the contents of the SCCS file directly. To change the delta comments, use
  the cdc(1) command.

  SCCS does not allow use of the delta command if an editable file does not
  exist.  However, once an editable file exists (created with get -e), SCCS
  creates the delta without checking the data being stored in the file.

  Do not use the delta command on a file if it contains expanded identifica-
  tion keywords.  Read-only file versions replace keywords with text values.
  Using delta on a read-only file causes the keywords to be lost.  If this
  happens, remove the delta with the rmdel command or re-edit the file and
  replace the identification keywords.	SCCS does not allow you to use delta
  unless an editable copy of the file exists.

  To prevent the loss of keywords, use the admin command with the -f flag to
  specify the i option.



EXAMPLES

   1.  To record changes you have made to an SCCS file, enter:
	    delta  s.prog.c


       This adds a delta to the SCCS file s.prog.c, records the changes made
       by editing prog.c.  delta then asks you for a comment that summarizes
       the changes you made.  Enter the comment, then press the End-of-File
       key sequence or press  twice to indicate that you have fin-
       ished the comment.

   2.  To record changes to an SCCS file and specify the comment for the
       delta on the command line, enter:
	    delta s.prog.c -y "Updated calendar function for 1993."


NOTES

  Lines beginning with an SOH ASCII character (binary 001) cannot be placed
  in the SCCS file unless the SOH is quoted using a \ (backslash).  SOH has
  special meaning to SCCS and causes an error.	See the sccsfile(4) reference
  page.

EXIT VALUES

  For information about exit values, see the -m flag description.

RELATED INFORMATION

  Commands:  admin(1), bdiff(1), cdc(1), comb(1), get(1), prs(1), rmdel(1),
  sact(1), sccsdiff(1), sccshelp(1), unget(1), val(1), what(1).

  Files:  sccsfile(4).

  Programming Support Tools