vc(1)

NAME

vc − version control program

SYNTAX

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 process of performing the copy operation, 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 standard output is conditional. It is 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 noncontrol 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(.). A numeric value is an unsigned string of digits. Keyword values should contain blanks or tabs.

Replacement of keywords by values occurs 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 uninterpreted control character may be included in a value by preceding it with \. If a literal \ is desired, then it too must be preceded by \.

OPTIONS

Keyletter arguments:

−aReplaces the keywords surrounded by control characters in all text lines.

−cchar
Specifies a control character to be used in place of :.

−sSuppresses all warning messages.

−tIgnores all characters from the beginning of the line to the first tab character. If one is found, all characters up to and including the tab are discarded.

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 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 solely for the purpose of maintaining the proper if-end matching.
The syntax of a condition is:

The available operators and their meanings are:

=equal
!=not equal
&and
|or
>greater than
<less than
( )used for logical groupings
notmay only occur immediately after the if, and
when present, inverts the value of the
entire condition

The > and < operate only on unsigned integer values. For example, : 012 > 12 is false). All other operators take strings as arguments. For example, fB: 012 != 12 is true). The precedence of the operators (from highest to lowest) is:

= != > < all of equal precedence
&
|

Parentheses can be used to alter the order of precedence.
Values must be separated from operators or parentheses by at least one blank or tab.

::text
Used for keyword replacement 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
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. The vc command halts execution, and returns an exit code of 1.

DIAGNOSTICS

Use help() for explanations.

EXIT CODES

0 − normal
1 − any error

Commands