NAME
    pcretest - a program for testing Perl-compatible regular expressions.

SYNOPSIS
    pcretest [-d] [-i] [-m] [-o osize] [-p] [-t] [source] [destination]

    pcretest  was written as a test program for the PCRE regular expression
    library itself, but it can also be used for experimenting with regular
    expressions. This man page describes the features of the test program;
    for details of the regular expressions themselves, see the pcre man
    page.

OPTIONS
    -d  Behave  as if each regex had the /D modifier (see below); the
   internal form is output after compilation.

    -i  Behave as if each regex had the /I modifier; information
   about the compiled pattern is given after compilation.

    -m  Output  the size of each compiled pattern after it has been
   compiled. This is equivalent to adding  /M to  each regular
   expression.  For compatibility with  earlier versions of
   pcretest, -s is a synonym for -m.

    -o osize  Set the number of elements in the output vector that is used
   when calling PCRE to be osize. The default value is 45, which
   is enough for 14 capturing subexpressions. The vector size
   can be changed for individual matching calls by including \O
   in the data line (see below).

    -p  Behave as if each regex has /P modifier; the POSIX wrapper
   API is used to call PCRE. None of the other options has any
   effect when -p is set.

    -t  Run each compile, study, and match 20000 times with a timer,
   and output resulting time per compile or match (in millisec-
   onds). Do not set -t with -m, because you will then get the
   size output 20000 times and the timing will be distorted.

DESCRIPTION
    If pcretest is  given two filename arguments, it reads from the first
    and writes to the second. If it is given only one filename argument, it
    reads from that file and writes to stdout. Otherwise, it reads from
    stdin and writes to stdout, and prompts for each line of  input,  using
    "re>" to prompt for regular expressions, and "data>" to prompt for data
    lines.

    The program handles any number of sets of input on a single input file.
    Each set starts with a regular expression, and continues with any num-
    ber of data lines to be matched against the pattern. An empty line sig-
    nals the end of the data lines, at which point a new regular expression
    is read. The regular expressions are given enclosed  in any non-
    alphameric delimiters other than backslash, for example

  /(a|bc)x+yz/

    White space before the initial delimiter is ignored. A regular expres-
    sion may be continued over several input lines, in which case the new-
    line characters  are included within it. It is possible to include the
    delimiter within the pattern by escaping it, for example

  /abc\/def/

    If you do so, the escape and the delimiter form part of  the pattern,
    but since delimiters are always non-alphameric, this does not affect
    its interpretation. If the terminating delimiter is immediately fol-
    lowed by a backslash, for example,

  /abc/\

    then a backslash is added to the end of the pattern. This is done to
    provide a way of testing the error condition that arises if a pattern
    finishes with a backslash, because

  /abc\/

    is interpreted as the first line of a pattern that starts with "abc/",
    causing pcretest to read the next line as a continuation of the regular
    expression.

PATTERN MODIFIERS
    The pattern may be followed by i, m, s, or x to set the PCRE_CASELESS,
    PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options,  respectively.
    For example:

  /caseless/i

    These modifier letters have the same effect as they do in Perl. There
    are others which set PCRE options that do not correspond to anything in
    Perl: /A, /E, and /X  set PCRE_ANCHORED, PCRE_DOLLAR_ENDONLY, and
    PCRE_EXTRA respectively.

    Searching for all possible matches within each subject string can be
    requested by the /g or /G modifier. After finding a match, PCRE is
    called again to search the remainder of the subject string. The differ-
    ence between /g and /G is that the former uses the startoffset argument
    to pcre_exec() to start searching at a new point within the entire
    string (which is in effect what Perl does), whereas the latter passes
    over a shortened substring. This makes a  difference to  the matching
    process if the pattern begins with a lookbehind assertion (including \b
    or \B).

    If any call to pcre_exec() in a /g or /G sequence matches an  empty
    string, the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED
    flags set in order to search for another, non-empty, match at the same
    point. If this second match fails, the start offset is advanced by
    one, and the normal match is retried. This imitates the way Perl han-
    dles such cases when using the /g modifier or the split() function.

    There are a number of other modifiers for controlling the way pcretest
    operates.

    The /+ modifier requests that as well as outputting the substring that
    matched the entire pattern, pcretest  should in addition output the
    remainder of the subject string. This is useful for tests where the
    subject contains multiple copies of the same substring.

    The /L modifier must be followed directly by the name of a locale, for
    example,

  /pattern/Lfr

    For this reason, it must be the last modifier letter. The given locale
    is set, pcre_maketables() is called to build a set of character tables
    for the locale, and this is then passed to pcre_compile() when compil-
    ing the  regular expression. Without an /L modifier, NULL is passed as
    the tables pointer; that is, /L applies only to the expression on which
    it appears.

    The /I modifier requests that pcretest output information about the
    compiled expression (whether it is anchored, has a fixed first charac-
    ter, and so on). It does this by calling pcre_fullinfo() after compil-
    ing an expression, and outputting the information it gets back. If the
    pattern is studied, the results of that are also output.

    The /D modifier is a PCRE debugging feature, which also assumes /I. It
    causes the internal form of compiled regular expressions to be output
    after compilation.

    The /S modifier causes pcre_study() to be called after the expression
    has been compiled, and the results used when the expression is matched.

    The /M modifier causes the size of memory block used to hold the com-
    piled pattern to be output.

    The /P modifier causes pcretest to call PCRE via the POSIX wrapper API
    rather than its native API. When this is done, all other modifiers
    except /i, /m, and /+ are ignored. REG_ICASE is set if /i is present,
    and REG_NEWLINE  is set if /m is present. The wrapper functions force
    PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.

    The /8 modifier causes pcretest to call PCRE with the PCRE_UTF8 option
    set. This turns on the (currently incomplete) support for UTF-8 charac-
    ter handling in PCRE, provided that it was compiled with this support
    enabled. This modifier also causes any non-printing characters in out-
    put strings to  be printed using the \x{hh...} notation if they are
    valid UTF-8 sequences.

DATA LINES
    Before each data line is passed to pcre_exec(), leading  and trailing
    whitespace is removed, and it is then scanned for \ escapes. The fol-
    lowing are recognized:

  \a   alarm (= BEL)
  \b   backspace
  \e   escape
  \f   formfeed
  \n   newline
  \r   carriage return
  \t   tab
  \v   vertical tab
  \nnn   octal character (up to 3 octal digits)
  \xhh   hexadecimal character (up to 2 hex digits)
  \x{hh...} hexadecimal UTF-8 character

  \A   pass the PCRE_ANCHORED option to pcre_exec()
  \B   pass the PCRE_NOTBOL option to pcre_exec()
  \Cdd   call pcre_copy_substring() for substring dd
      after a successful match (any decimal number
      less than 32)
  \Gdd   call pcre_get_substring() for substring dd
      after a successful match (any decimal number
      less than 32)
  \L   call pcre_get_substringlist() after a
      successful match
  \N   pass the PCRE_NOTEMPTY option to pcre_exec()
  \Odd   set the size of the output vector passed to
      pcre_exec() to dd (any number of decimal
      digits)
  \Z   pass the PCRE_NOTEOL option to pcre_exec()

    When \O is used, it may be higher or lower than the size set by the -O
    option (or defaulted to 45); \O applies only to the call of pcre_exec()
    for the line in which it appears.

    A backslash followed by anything else just escapes the anything  else.
    If the very last character is a backslash, it is ignored. This gives a
    way of passing an empty line as data, since a real empty line termi-
    nates the data input.

    If /P was present on the regex, causing the POSIX wrapper API to be
    used, only 0 causing REG_NOTBOL and REG_NOTEOL to be passed to
    regexec() respectively.

    The use of \x{hh...} to represent UTF-8 characters is not dependent on
    the use of the /8 modifier on the pattern. It is recognized always.
    There may be any number of hexadecimal digits inside the braces. The
    result is from one to six bytes, encoded according to the UTF-8 rules.

OUTPUT FROM PCRETEST
    When a match succeeds, pcretest outputs the list of captured substrings
    that pcre_exec() returns, starting with number 0 for the string that
    matched the whole pattern. Here is an example of an interactive
    pcretest run.

  $ pcretest
  PCRE version 2.06 08-Jun-1999

   re> /^abc(\d+)/
  data> abc123
  0: abc123
  1: 123
  data> xyz
  No match

    If the strings contain any non-printing characters, they are output as
    \0x escapes, or as \x{...} escapes if the /8 modifier was present on
    the pattern. If the pattern has the /+ modifier, then the output for
    substring 0 is followed by the the rest of the subject string, identi-
    fied by "0+" like this:

   re> /cat/+
  data> cataract
  0: cat
  0+ aract

    If the pattern has the /g or /G modifier, the results of successive
    matching attempts are output in sequence, like this:

   re> /\Bi(\w\w)/g
  data> Mississippi
  0: iss
  1: ss
  0: iss
  1: ss
  0: ipp
  1: pp

    "No match" is output only if the first match attempt fails.

    If any of the sequences \C, \G, or \L are present in a data line that
    is successfully matched, the substrings extracted by the convenience
    functions are output with C, G, or L after the string number instead of
    a colon. This is in addition to the normal full list. The string length
    (that is, the return from the extraction function) is given in paren-
    theses after each string for \C and \G.

    Note that while patterns can be continued over several lines (a  plain
    ">" prompt is used for continuations), data lines may not. However new-
    lines can be included in data by means of the \n escape.

AUTHOR
    Philip Hazel <ph10@cam.ac.uk>
    University Computing Service,
    New Museums Site,
    Cambridge CB2 3QG, England.
    Phone: +44 1223 334714

    Last updated: 15 August 2001
    Copyright (c) 1997-2001 University of Cambridge.