The R Configuration Command
Rules are declared in the configuration file with the R
configuration command.
Like all configuration commands, the R
rule configuration
command must begin a line. The general form consists of an
R
command
followed by three parts:
Rlhs rhs comment ↑ ↑ tabs tabs
The lhs
stands for
lefthand side and is most
commonly expressed as LHS. The rhs
stands for righthand
side and is expressed as RHS. The LHS and
RHS are mandatory. The third part (the comment
) is optional. The
three parts must be separated from each other by one or more
tab characters (space characters will
not work).
Space characters between the R
and the LHS are optional. If there is a
tab between the R
and the
LHS, sendmail prints and logs the
following error:
configfile: line number: R line: null LHS
Space characters can be used inside any of the three parts: the LHS, RHS, or comment. They are often used in those parts to make rules clearer and easier to parse visually.
The tabs leading to the comment and the comment itself are
optional and can be omitted. If the RHS is absent,
sendmail prints the following
warning and ignores that R
line:
invalid rewrite line "bad rule here" (tab expected)
This error is printed when the RHS is absent, even if there are tabs following the LHS. (This warning is usually the result of tabs being converted to spaces when text is copied from one window to another in a windowing system using cut and paste.)
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