delta(1)

NAME

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

SYNOPSIS

delta [-r SID ] [-s] [-n] [-g list] [-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 (called the g-file, or generated file). See get(1).

delta makes a delta to each named SCCS file. If a directory is named, delta behaves as though each file in the directory was 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.

delta may issue prompts on the standard output, depending upon certain options specified and flags (see admin(1)) that may be present in the SCCS file (see the -m and -y options below).

Options

Option arguments apply independently to each named file.

-rSID

Uniquely identifies which delta is to be made to the SCCS file. 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(1)). A diagnostic results if the specified SID is ambiguous, or, if necessary and omitted on the command line.

-s

Suppresses issuing, 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

Specifies a list (see get(1) 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(1)), 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 the -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(1)), it is assumed to be the name of a program (or shell procedure) that is to validate the correctness of the MR numbers. If a non-zero exit status is returned from the MR number-validation program, delta assumes that the MR numbers were not all valid and terminates.

-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 in a diff(1) format) the SCCS file differences before and after the delta is applied.

EXTERNAL INFLUENCES

Environment Variables

LC_CTYPE determines the interpretation of text as single- and/or multi-byte characters.

LC_MESSAGES determines the language in which messages are displayed.

If LC_CTYPE or LC_MESSAGES is not specified in the environment or is set to the empty string, the value of LANG is used as a default for each unspecified or empty variable. If LANG is not specified or is set to the empty string, a default of "C" (see lang(5)) is used instead of LANG. If any internationalization variable contains an invalid setting, delta behaves as if all internationalization variables are set to "C". See environ(5).

International Code Set Support

Single- and multi-byte character code sets are supported.

DIAGNOSTICS

Use sccshelp(1) for explanations.

WARNINGS

SCCS files can be any length, but the number of lines in the text file itself cannot exceed 99999 lines.

Lines beginning with an ASCII SOH character (octal 001) cannot be placed in the SCCS file unless the SOH is escaped. This character has special meaning to SCCS (see sccsfile(4)) 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 options must also be present. Omission of these options causes an error.

Comments can be of multiple lines. The maximum length of the comment (total length of all comment lines) cannot exceed 1024 bytes. No line in a comment should have a length of more than 1000 bytes.

FILES

All of the auxiliary files listed below, except for the g-file, are created in the same directory as the s-file (see get(1)). The g-file is created in the user's working directory.

g-file: Existed before the execution of delta; removed after completion of delta (unless -n was specified).
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 file retrieved by get and the g-file.

STANDARDS CONFORMANCE

delta: SVID2, SVID3, XPG2, XPG3, XPG4