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PCRE_TABLE(5)		      File Formats Manual		 PCRE_TABLE(5)

NAME
       pcre_table - format of Postfix PCRE tables

SYNOPSIS
       postmap -q "string" pcre:$config_directory/filename

       postmap -q - pcre:$config_directory/filename <inputfile

DESCRIPTION
       The  Postfix  mail  system  uses	optional tables	for address rewriting,
       mail routing, or	access control.	These tables are usually in dbm	or  db
       format.

       Alternatively,  lookup tables can be specified in Perl Compatible Regu-
       lar Expression form. In this case, each input  is  compared  against  a
       list  of	 patterns.  When a match is found, the corresponding result is
       returned	and the	search is terminated.

       To find out what	types of lookup	tables your  Postfix  system  supports
       use the "postconf -m" command.

       To test lookup tables, use the "postmap -q" command as described	in the
       SYNOPSIS	above.

COMPATIBILITY
       With Postfix version 2.2	and earlier specify "postmap -fq" to  query  a
       table that contains case	sensitive patterns. Patterns are case insensi-
       tive by default.

TABLE FORMAT
       The general form	of a PCRE table	is:

       /pattern/flags result
	      When pattern matches the input string, use the corresponding re-
	      sult value.

       !/pattern/flags result
	      When  pattern  does  not	match the input	string,	use the	corre-
	      sponding result value.

       if /pattern/flags

       endif  Match the	input string against the patterns between if  and  en-
	      dif, if and only if that same input string also matches pattern.
	      The if..endif can	nest.

	      Note: do not prepend whitespace to patterns inside if..endif.

	      This feature is available	in Postfix 2.1 and later.

       if !/pattern/flags

       endif  Match the	input string against the patterns between if  and  en-
	      dif,  if	and only if that same input string does	not match pat-
	      tern. The	if..endif can nest.

	      Note: do not prepend whitespace to patterns inside if..endif.

	      This feature is available	in Postfix 2.1 and later.

       blank lines and comments
	      Empty lines and whitespace-only lines are	ignored, as are	 lines
	      whose first non-whitespace character is a	`#'.

       multi-line text
	      A	 logical  line	starts	with  non-whitespace text. A line that
	      starts with whitespace continues a logical line.

       Each pattern is a perl-like regular expression. The  expression	delim-
       iter  can  be  any  non-alphanumerical  character, except whitespace or
       characters that have special meaning (traditionally the	forward	 slash
       is used).  The regular expression can contain whitespace.

       By  default, matching is	case-insensitive, and newlines are not treated
       as special characters. The behavior is controlled by flags,  which  are
       toggled	by appending one or more of the	following characters after the
       pattern:

       i (default: on)
	      Toggles the case sensitivity flag. By default, matching is  case
	      insensitive.

       m (default: off)
	      Toggles the PCRE_MULTILINE flag. When this flag is on, the ^ and
	      $	metacharacters match immediately after and immediately	before
	      a	 newline  character,  respectively, in addition	to matching at
	      the start	and end	of the subject string.

       s (default: on)
	      Toggles the PCRE_DOTALL flag.  When  this	 flag  is  on,	the  .
	      metacharacter  matches  the newline character. With Postfix ver-
	      sions prior to 2.0, the flag is off by default, which is	incon-
	      venient for multi-line message header matching.

       x (default: off)
	      Toggles the pcre extended	flag. When this	flag is	on, whitespace
	      characters in the	pattern	(other than in a character class)  are
	      ignored.	 To include a whitespace character as part of the pat-
	      tern, escape it with backslash.

	      Note: do not use #comment	after patterns.

       A (default: off)
	      Toggles the PCRE_ANCHORED	flag.  When this flag is on, the  pat-
	      tern  is	forced to be "anchored", that is, it is	constrained to
	      match only at the	start of the string which  is  being  searched
	      (the  "subject string"). This effect can also be achieved	by ap-
	      propriate	constructs in the pattern itself.

       E (default: off)
	      Toggles the PCRE_DOLLAR_ENDONLY flag. When this flag is on, a  $
	      metacharacter in the pattern matches only	at the end of the sub-
	      ject string. Without this	flag, a	dollar	also  matches  immedi-
	      ately  before  the  final	character if it	is a newline character
	      (but not before any other	newline	characters). This flag is  ig-
	      nored if PCRE_MULTILINE flag is set.

       U (default: off)
	      Toggles  the  ungreedy matching flag.  When this flag is on, the
	      pattern matching engine inverts the "greediness" of the  quanti-
	      fiers  so	that they are not greedy by default, but become	greedy
	      if followed by "?".  This	flag can also set by a	(?U)  modifier
	      within the pattern.

       X (default: off)
	      Toggles  the  PCRE_EXTRA	flag.  When this flag is on, any back-
	      slash in a pattern that is followed by a letter that has no spe-
	      cial  meaning causes an error, thus reserving these combinations
	      for future expansion.

SEARCH ORDER
       Patterns	are applied in the order as specified in the  table,  until  a
       pattern is found	that matches the input string.

       Each  pattern  is applied to the	entire input string.  Depending	on the
       application, that string	is an entire client hostname, an entire	client
       IP  address, or an entire mail address.	Thus, no parent	domain or par-
       ent network search is done, and user@domain mail	addresses are not bro-
       ken  up	into  their user and domain constituent	parts, nor is user+foo
       broken up into user and foo.

TEXT SUBSTITUTION
       Substitution of substrings (text	that  matches  patterns	 inside	 "()")
       from  the  matched  expression into the result string is	requested with
       $1, $2, etc.; specify $$	to produce  a  $  character  as	 output.   The
       macros  in  the result string may need to be written as ${n} or $(n) if
       they aren't followed by whitespace.

       Note: since negated patterns (those preceded by !) return a result when
       the  expression	does  not  match,  substitutions are not available for
       negated patterns.

EXAMPLE	SMTPD ACCESS MAP
       # Protect your outgoing majordomo exploders
       /^(?!owner-)(.*)-outgoing@(.*)/ 550 Use ${1}@${2} instead

       # Bounce	friend@whatever, except	when whatever is our domain (you would
       # be better just	bouncing all friend@ mail - this is just an example).
       /^(friend@(?!my\.domain$).*)$/  550 Stick this in your pipe $1

       # A multi-line entry. The text is sent as one line.
       #
       /^noddy@my\.domain$/
	550 This user is a funny one. You really don't want to send mail to
	them as	it only	makes their head spin.

EXAMPLE	HEADER FILTER MAP
       /^Subject: make money fast/     REJECT
       /^To: friend@public\.com/       REJECT

EXAMPLE	BODY FILTER MAP
       # First skip over base 64 encoded text to save CPU cycles.
       # Requires PCRE version 3.
       ~^[[:alnum:]+/]{60,}$~	       OK

       # Put your own body patterns here.

SEE ALSO
       postmap(1), Postfix lookup table	manager
       postconf(5), configuration parameters
       regexp_table(5),	format of POSIX	regular	expression tables

README FILES
       Use "postconf readme_directory" or "postconf html_directory" to	locate
       this information.
       DATABASE_README,	Postfix	lookup table overview

AUTHOR(S)
       The PCRE	table lookup code was originally written by:
       Andrew McNamara
       andrewm@connect.com.au
       connect.com.au Pty. Ltd.
       Level 3,	213 Miller St
       North Sydney, NSW, Australia

       Adopted and adapted by:
       Wietse Venema
       IBM T.J.	Watson Research
       P.O. Box	704
       Yorktown	Heights, NY 10598, USA

								 PCRE_TABLE(5)

NAME | SYNOPSIS | DESCRIPTION | COMPATIBILITY | TABLE FORMAT | SEARCH ORDER | TEXT SUBSTITUTION | EXAMPLE SMTPD ACCESS MAP | EXAMPLE HEADER FILTER MAP | EXAMPLE BODY FILTER MAP | SEE ALSO | README FILES | AUTHOR(S)

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