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       postmap -q "string" pcre:/etc/postfix/filename

       postmap -q - pcre:/etc/postfix/filename <inputfile


       The  Postfix  mail system uses optional tables for address
       rewriting or mail routing. These tables are usually in dbm
       or  db  format. Alternatively, lookup tables can be speci­
       fied in Perl Compatible Regular Expression form.

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

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

       The general form of a PCRE table is:

       /pattern/flags result
              When pattern matches a search string, use the  cor­
              responding result value.

       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  logi­
              cal line.

       if /pattern/flags

       if !/pattern/flags

       endif  Match   the  search  string  against  the  patterns
              between if and endif, if and  only  if  the  search
              string   matches  (does  not  match)  pattern.  The
              if..endif can nest.

              Note: do not prepend whitespace to patterns  inside

       Each  pattern  is  a  perl-like  regular  expression.  The
       expression delimiter can be any character, except  whites­
       pace  or  characters that have special meaning (tradition­
       ally the forward slash is used).  The  regular  expression
       can contain whitespace.
              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  versions prior to 20020528, The flag
              is off by default, which is inconvenient for multi-
              line message header matching.

       x (default: off)
              Toggles  the  pcre extended flag. When this flag is
              on, whitespace in the  pattern  (other  than  in  a
              character class) and characters between a # outside
              a character class and the  next  newline  character
              are  ignored.  An escaping backslash can be used to
              include a whitespace or # character as part of  the

       A (default: off)
              Toggles  the PCRE_ANCHORED flag.  When this flag is
              on, the pattern 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
              appropriate 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  subject  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 charac­
              ters). This flag is ignored 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  quantifiers so that they are
              not greedy by default, but become  greedy  if  fol­
              lowed  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  backslash  in  a pattern that is followed by a
              letter that has no special meaning causes an error,
              thus reserving these combinations for future expan­

       perl syntax ($1, $2, etc.).   The  macros  in  the  result
       string  may  need  to  be  written as ${n} or $(n) if they
       aren't followed by whitespace.


       # 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 $0

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


       /^Subject: make money fast/     REJECT
       /^To: friend@public\.com/       REJECT


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

       # Put your own body patterns here.


       regexp_table(5) format of POSIX regular expression tables


       The PCRE table lookup code was originally written by:
       Andrew McNamara
       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




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