vc(1) DG/UX 5.4.2 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 is found, all characters up to and
including the tab are discarded.
-cchar Specifies a control character to be used in place
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vc(1) DG/UX 5.4.2 vc(1)
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
( ) 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
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vc(1) DG/UX 5.4.2 vc(1)
> 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.
DIAGNOSTICS
Use help(1) for explanations.
EXIT CODES
0--Normal
1--Any error
SEE ALSO
ed(1), help(1).
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