VC(1) INTERACTIVE UNIX System 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. In the pro-
cess of performing the copy operation, user declared key-
words 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 state-
ments) of keyword values specified in control statements or
as vc command arguments.
A control statement is a single line beginning with a con-
trol 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 charac-
ter 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. An uninter-
preted control character may be included 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 con-
trol characters with their assigned value in all
text lines and 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.
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VC(1) INTERACTIVE UNIX System VC(1)
-cchar Specifies a control character to be used in place
of :.
-s Silences warning messages (not error) that are nor-
mally printed on the diagnostic output.
Version Control Statements
:dcl keyword[, ..., keyword]
Used to declare keywords. All keywords must be
declared.
:asg keyword=value
Used to assign 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
Used to skip lines of the standard input. If the con-
dition 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 solely for the purpose of
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 only occur immediately after the if, and
when present, inverts the value of the entire
condition
The > and < operate only on unsigned integer values
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VC(1) INTERACTIVE UNIX System VC(1)
(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
&
|
Parentheses may be used to alter the order of pre-
cedence.
Values must be separated from operators or parentheses
by at least one blank or tab.
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VC(1) INTERACTIVE UNIX System VC(1)
::text
Used for keyword replacement on lines that are copied
to the standard output. The two leading control char-
acters 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 Turn on or off keyword replacement on all lines.
:ctl char
Change 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) in the INTERACTIVE UNIX System User's/System
Administrator's Reference Manual.
EXIT CODES
0 - normal
1 - any error
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