Originální popis anglicky:
delta - make a delta (change) to an SCCS file (
DEVELOPMENT)
Návod, kniha: POSIX Programmer's Manual
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
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 .
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
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.
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 .
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:
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.
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.
Utility Description Defaults ,
admin ,
diff ,
get ,
prs ,
rmdel
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
.
