vc(1) DG/UX 4.30 vc(1)
NAME
vc - version control
SYNOPSIS
vc [-a] [-t] [-cchar] [-s] [keyword=value ... keyword=value]
DESCRIPTION
The vc command copies lines from the standard input to the
standard output under control of its arguments and control
statements encountered in the standard input. User-declared
keywords may be replaced by their string value when they
appear in plain text and/or control statements.
The copying of lines from the standard input to the standard
output is conditional, based on tests (in control
statements) of keyword values specified in control
statements or as vc command arguments.
A control statement is a single line beginning with a
control character, except as modified by the -t keyletter
(see below). The default control character is colon (:),
except as modified by the -c keyletter (see below). Input
lines beginning with a backslash (\) followed by a control
character are not control lines and are copied to the
standard output with the backslash removed. Lines beginning
with a backslash followed by a non-control character are
copied in their entirety.
A keyword is composed of 9 or fewer alphanumerics; the first
must be alphabetic. A value is any ASCII string that can be
created with ed(1); a numeric value is an unsigned string of
digits. Keyword values may not contain blanks or tabs.
Replacement of keywords by values is done whenever a keyword
surrounded by control characters is encountered on a version
control statement. The -a keyletter (see below) forces
replacement of keywords in all lines of text. You can
include an uninterpreted control character in a value by
preceding it with \. If a literal \ is desired, then it too
must be preceded by \.
Keyletter Arguments
-a Forces replacement of keywords
surrounded by control characters with
their assigned value in all text lines,
not just in vc statements.
-t All characters from the beginning of a
line up to and including the first tab
character are ignored for the purpose of
detecting a control statement. If one
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vc(1) DG/UX 4.30 vc(1)
is found, all characters up to and
including the tab are discarded.
-cchar Specifies a control character to be used
in place of :.
-s Silences warning messages (not error)
that are normally printed on the
diagnostic output.
Version Control Statements
:dcl keyword[, ..., keyword]
Declares keywords. All keywords must be declared.
:asg keyword=value
Assigns values to keywords. An asg statement overrides
the assignment for the corresponding keyword on the vc
command line and all previous asg's for that keyword.
Keywords declared, but not assigned values, have null
values.
:if condition
.
.
.
:end
Skips lines of the standard input. If the condition is
true all lines between the if statement and the
matching end statement are copied to the standard
output. If the condition is false, all intervening
lines are discarded, including control statements.
Note that intervening if statements and matching end
statements are recognized only for maintaining the
proper if-end matching.
The syntax of a condition is:
<cond> ::= [ "not" ] <or>
<or> ::= <and> | <and> "|" <or>
<and> ::= <exp> | <exp> "&" <and>
<exp> ::= "(" <or> ")" | <value> <op> <value>
<op> ::= "=" | "!=" | "<" | ">"
<value> ::= <arbitrary ASCII string> | <numeric string>
The available operators and their meanings are:
= Equal
!= Not equal
& And
| Or
> Greater than
< Less than
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vc(1) DG/UX 4.30 vc(1)
( ) Used for logical groupings
not May occur only immediately after the if, and
when present, inverts the value of the
entire condition
The > and < operate only on unsigned integer values
(e.g., : 012 > 12 is false). All other operators take
strings as arguments (e.g., : 012 != 12 is true). The
precedence of the operators (from highest to lowest)
is:
= != > < All of equal precedence
&
|
Use parentheses to alter the order of precedence.
Separate values from operators or parentheses by at
least one blank or tab.
::text
Replaces keywords on lines that are copied to the
standard output. The two leading control characters
are removed, and keywords surrounded by control
characters in text are replaced by their value before
the line is copied to the output file. This action is
independent of the -a keyletter.
:on
:off
Turns on or off keyword replacement on all lines.
:ctl char
Changes the control character to char.
:msg message
Prints the given message on the diagnostic output.
:err message
Prints the given message followed by:
ERROR: err statement on line ... (915)
on the diagnostic output. Vc halts execution, and
returns an exit code of 1.
SEE ALSO
ed(1), help(1).
DIAGNOSTICS
Use help(1) for explanations.
EXIT CODES
0--Normal
1--Any error
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