delta(CP)

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

Syntax

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

Description

The delta command is used to 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 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 options specified and flags (see admin(CP)) that may be present in the SCCS file (see -m and -y options below).

Options apply independently to each named file.

-rSID

Uniquely identifies which delta is to be made to the SCCS file. The use of this option 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 option 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 option).

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 validates 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 standard output before standard input is read; if 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 standard output) the SCCS file differences before and after the delta is applied in a diff(C) format.

Files

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

Warnings

Lines beginning with an ASCII SOH character (binary 001) cannot be placed in the SCCS file unless the SOH is escaped. This character has special meaning to SCCS (see sccsfile(FP)) 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 standard input (``-'') is specified on the delta command line, the -m (if necessary) and -y options must also be present. Omission of these options causes an error.

Comments are limited to text strings of at most 1020 characters.

Line lengths greater than 1000 bytes may cause undefined behavior.

Any change which results in more than 99,999 lines being deleted, inserted or remaining the same will result in an error message and may corrupt the data.

Standards conformance

delta is conformant with: