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PROLOG | NAME | SYNOPSIS | DESCRIPTION | OPTIONS | OPERANDS | STDIN | INPUT FILES | ENVIRONMENT VARIABLES | ASYNCHRONOUS EVENTS | STDOUT | STDERR | OUTPUT FILES | EXTENDED DESCRIPTION | EXIT STATUS | CONSEQUENCES OF ERRORS | APPLICATION USAGE | EXAMPLES | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT |
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DELTA(1P) POSIX Programmer's Manual DELTA(1P)
This manual page is part of the POSIX Programmer's Manual. The
Linux implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior), or
the interface may not be implemented on Linux.
delta — make a delta (change) to an SCCS file (DEVELOPMENT)
delta [-nps] [-g list] [-m mrlist] [-r SID] [-y[comment]] file...
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).
The delta utility shall conform to the Base Definitions volume of
POSIX.1‐2017, 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(1p).
-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(1p) 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(1p).
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> characters
or escaped <newline> characters. 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(1p).
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.
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 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.
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 POSIX.1‐2017, 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.
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 Section 1.4, Utility Description
Defaults.
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>
The standard error shall be used only for diagnostic messages.
Any SCCS files updated shall be files of an unspecified format.
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.
The following exit values shall be returned:
0 Successful completion.
>0 An error occurred.
Default.
The following sections are informative.
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.
None.
None.
None.
Section 1.4, Utility Description Defaults, admin(1p), diff(1p),
get(1p), prs(1p), rmdel(1p)
The Base Definitions volume of POSIX.1‐2017, Chapter 8,
Environment Variables, Section 12.2, Utility Syntax Guidelines
Portions of this text are reprinted and reproduced in electronic
form from IEEE Std 1003.1-2017, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The
Open Group Base Specifications Issue 7, 2018 Edition, Copyright
(C) 2018 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 .
Any typographical or formatting errors that appear in this page
are most likely to have been introduced during the conversion of
the source files to man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2017 DELTA(1P)
Pages that refer to this page: admin(1p), get(1p), prs(1p), rmdel(1p), sact(1p), sccs(1p), unget(1p), val(1p)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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