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NAME
delta - make a delta (change) to an SCCS file (DEVELOPMENT)
SYNOPSIS
delta [-nps][-g list][-m mrlist][-r SID][-y[comment]] file...
DESCRIPTION
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).
OPTIONS
The delta utility shall conform to the Base Definitions volume of IEEE Std 1003.1-2001,
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
processing).
-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 delta.
-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>s or escaped <newline>s. 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.)
-y[comment]
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 .
OPERANDS
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 ignored.
STDIN
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
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.
ENVIRONMENT VARIABLES
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 IEEE Std 1003.1-2001, 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).
LC_MESSAGES
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 used.
ASYNCHRONOUS EVENTS
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 Utility
Description Defaults .
STDOUT
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>
STDERR
The standard error shall be used only for diagnostic messages.
OUTPUT FILES
Any SCCS files updated shall be files of an unspecified format.
EXTENDED DESCRIPTION
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.
EXIT STATUS
The following exit values shall be returned:
0 Successful completion.
>0 An error occurred.
CONSEQUENCES OF ERRORS
Default.
The following sections are informative.
APPLICATION USAGE
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.
EXAMPLES
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
Utility Description Defaults , admin , diff , get , prs , rmdel
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std
1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System
Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 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 http://www.opengroup.org/unix/online.html .