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ZSHEXPN(1)									       ZSHEXPN(1)

       zshexpn - zsh expansion and substitution

       The following types of expansions are performed in the indicated order in five steps:

       History Expansion
	      This is performed only in interactive shells.

       Alias Expansion
	      Aliases  are  expanded  immediately  before the command line is parsed as explained
	      under Aliasing in zshmisc(1).

       Process Substitution
       Parameter Expansion
       Command Substitution
       Arithmetic Expansion
       Brace Expansion
	      These five are performed in one step in left-to-right fashion.  After these  expan-
	      sions, all unquoted occurrences of the characters `\', `'' and `"' are removed.

       Filename Expansion
	      If the SH_FILE_EXPANSION option is set, the order of expansion is modified for com-
	      patibility with sh and ksh.  In that case filename expansion is  performed  immedi-
	      ately after alias expansion, preceding the set of five expansions mentioned above.

       Filename Generation
	      This expansion, commonly referred to as globbing, is always done last.

       The following sections explain the types of expansion in detail.

       History	expansion allows you to use words from previous command lines in the command line
       you are typing.	This simplifies spelling corrections and the  repetition  of  complicated
       commands or arguments.  Immediately before execution, each command is saved in the history
       list, the size of which is controlled by the HISTSIZE parameter.  The one most recent com-
       mand  is  always retained in any case.  Each saved command in the history list is called a
       history event and is assigned a number, beginning with 1 (one) when the shell  starts  up.
       The history number that you may see in your prompt (see Prompt Expansion in zshmisc(1)) is
       the number that is to be assigned to the next command.

       A history expansion begins with the first character of the histchars parameter,	which  is
       `!'  by	default,  and  may  occur anywhere on the command line; history expansions do not
       nest.  The `!' can be escaped with `\' or can be enclosed between a pair of single  quotes
       ('')  to  suppress  its special meaning.  Double quotes will not work for this.	Following
       this history character is an optional event designator (see the	section  `Event  Designa-
       tors')  and  then an optional word designator (the section `Word Designators'); if neither
       of these designators is present, no history expansion occurs.

       Input lines containing history expansions are echoed after being expanded, but before  any
       other  expansions take place and before the command is executed.  It is this expanded form
       that is recorded as the history event for later references.

       By default, a history reference with no event designator refers to the same event  as  any
       preceding history reference on that command line; if it is the only history reference in a
       command, it refers to the previous command.  However, if the option CSH_JUNKIE_HISTORY  is
       set,  then every history reference with no event specification always refers to the previ-
       ous command.

       For example, `!' is the event designator for the previous command, so `!!:1' always refers
       to the first word of the previous command, and `!!$' always refers to the last word of the
       previous command.  With CSH_JUNKIE_HISTORY set, then `!:1' and `!$' function in	the  same
       manner  as  `!!:1'  and	`!!$', respectively.  Conversely, if CSH_JUNKIE_HISTORY is unset,
       then `!:1' and `!$' refer to the first and last words, respectively,  of  the  same  event
       referenced  by  the  nearest other history reference preceding them on the current command
       line, or to the previous command if there is no preceding reference.

       The character sequence `^foo^bar' (where `^' is	actually  the  second  character  of  the
       histchars  parameter)  repeats  the last command, replacing the string foo with bar.  More
       precisely, the sequence `^foo^bar^' is synonymous with `!!:s^foo^bar^', hence other  modi-
       fiers (see the section `Modifiers') may follow the final `^'.

       If  the	shell encounters the character sequence `!"'  in the input, the history mechanism
       is temporarily disabled until the current list (see zshmisc(1)) is fully parsed.  The `!"'
       is removed from the input, and any subsequent `!' characters have no special significance.

       A  less	convenient but more comprehensible form of command history support is provided by
       the fc builtin.

   Event Designators
       An event designator is a reference to a command-line entry in the history  list.   In  the
       list below, remember that the initial `!' in each item may be changed to another character
       by setting the histchars parameter.

       !      Start a history expansion, except when followed by a blank, newline,  `='  or  `('.
	      If  followed immediately by a word designator (see the section `Word Designators'),
	      this forms a history reference with no event designator  (see  the  section  `Over-

       !!     Refer to the previous command.  By itself, this expansion repeats the previous com-

       !n     Refer to command-line n.

       !-n    Refer to the current command-line minus n.

       !str   Refer to the most recent command starting with str.

	      Refer to the most recent command containing str.	The trailing `?' is necessary  if
	      this  reference is to be followed by a modifier or followed by any text that is not
	      to be considered part of str.

       !#     Refer to the current command line typed in so far.  The line is treated  as  if  it
	      were complete up to and including the word before the one with the `!#' reference.

       !{...} Insulate a history reference from adjacent characters (if necessary).

   Word Designators
       A word designator indicates which word or words of a given command line are to be included
       in a history reference.	A `:' usually separates the event  specification  from	the  word
       designator.   It  may  be omitted only if the word designator begins with a `^', `$', `*',
       `-' or `%'.  Word designators include:

       0      The first input word (command).
       n      The nth argument.
       ^      The first argument.  That is, 1.
       $      The last argument.
       %      The word matched by (the most recent) ?str search.
       x-y    A range of words; x defaults to 0.
       *      All the arguments, or a null value if there are none.
       x*     Abbreviates `x-$'.
       x-     Like `x*' but omitting word $.

       Note that a `%' word designator works only when used in one of `!%', `!:%' or  `!?str?:%',
       and  only  when used after a !? expansion (possibly in an earlier command).  Anything else
       results in an error, although the error may not be the most obvious one.

       After the optional word designator, you can add a sequence of one or more of the following
       modifiers,  each  preceded  by a `:'.  These modifiers also work on the result of filename
       generation and parameter expansion, except where noted.

       h      Remove a trailing pathname component, leaving the head.  This works like `dirname'.

       r      Remove a filename extension of the form `.xxx', leaving the root name.

       e      Remove all but the extension.

       t      Remove all leading pathname components, leaving the tail.  This works  like  `base-

       p      Print the new command but do not execute it.  Only works with history expansion.

       q      Quote  the  substituted  words, escaping further substitutions.  Works with history
	      expansion and parameter expansion, though for parameters it is only useful  if  the
	      resulting text is to be re-evaluated such as by eval.

       Q      Remove one level of quotes from the substituted words.

       x      Like  q,	but  break into words at whitespace.  Does not work with parameter expan-

       l      Convert the words to all lowercase.

       u      Convert the words to all uppercase.

	      Substitute r for l as described below.  Unless preceded immediately by a g, with no
	      colon  between,  the substitution is done only for the first string that matches l.
	      For arrays and for filename generation, this applies to each word of  the  expanded

       &      Repeat  the  previous  s substitution.  Like s, may be preceded immediately by a g.
	      In parameter expansion the & must appear inside braces, and in filename  generation
	      it must be quoted with a backslash.

       The  s/l/r/  substitution  works  as follows.  The left-hand side of substitutions are not
       regular expressions, but character strings.  Any character can be used as the delimiter in
       place  of  `/'.	 A  backslash  quotes the delimiter character.	The character `&', in the
       right-hand-side r, is replaced by the text from the left-hand-side  l.	The  `&'  can  be
       quoted  with a backslash.  A null l uses the previous string either from the previous l or
       from the contextual scan string s from `!?s'.  You can omit the rightmost delimiter  if	a
       newline	immediately follows r; the rightmost `?' in a context scan can similarly be omit-
       ted.  Note the same record of the last l and r is maintained across all	forms  of  expan-

       The following f, F, w and W modifiers work only with parameter expansion and filename gen-
       eration.  They are listed here to provide a single point of reference for all modifiers.

       f      Repeats the immediately (without a colon) following modifier  until  the	resulting
	      word doesn't change any more.

	      Like  f, but repeats only n times if the expression expr evaluates to n.	Any char-
	      acter can be used instead of the `:'; if `(', `[', or `{' is used  as  the  opening
	      delimiter, the closing delimiter should be ')', `]', or `}', respectively.

       w      Makes the immediately following modifier work on each word in the string.

       W:sep: Like w but words are considered to be the parts of the string that are separated by
	      sep. Any character can be used instead of the `:'; opening parentheses are  handled
	      specially, see above.

       Each  command argument of the form `<(list)', `>(list)' or `=(list)' is subject to process
       substitution.  In the case of the <  or	>  forms,  the	shell  runs  process  list  asyn-
       chronously.   If  the  system  supports the /dev/fd mechanism, the command argument is the
       name of the device file corresponding to a file descriptor; otherwise, if the system  sup-
       ports  named pipes (FIFOs), the command argument will be a named pipe.  If the form with >
       is selected then writing on this special file will provide input for list.  If < is  used,
       then  the  file passed as an argument will be connected to the output of the list process.
       For example,

	      paste <(cut -f1 file1) <(cut -f3 file2) |
	      tee >(process1) >(process2) >/dev/null

       cuts fields 1 and 3 from the files  file1  and  file2  respectively,  pastes  the  results
       together, and sends it to the processes process1 and process2.

       Both  the  /dev/fd  and the named pipe implementation have drawbacks.  In the former case,
       some programmes may automatically close the file descriptor in question	before	examining
       the  file on the command line, particularly if this is necessary for security reasons such
       as when the programme is running setuid.  In the second case, if the  programme	does  not
       actually open the file, the subshell attempting to read from or write to the pipe will (in
       a typical implementation, different operating systems may have different behaviour)  block
       for ever and have to be killed explicitly.  In both cases, the shell actually supplies the
       information using a pipe, so that programmes that expect to lseek (see  lseek(2))  on  the
       file will not work.

       Also  note  that  the previous example can be more compactly and efficiently written (pro-
       vided the MULTIOS option is set) as:

	      paste <(cut -f1 file1) <(cut -f3 file2) \
	      > >(process1) > >(process2)

       The shell uses pipes instead of FIFOs to implement the latter two process substitutions in
       the above example.

       If  =  is  used,  then the file passed as an argument will be the name of a temporary file
       containing the output of the list process.  This may be used instead of the < form  for	a
       program that expects to lseek (see lseek(2)) on the input file.

       The  character  `$'  is	used  to  introduce  parameter expansions.  See zshparam(1) for a
       description of parameters, including arrays, associative arrays, and subscript notation to
       access individual array elements.

       In  the	expansions discussed below that require a pattern, the form of the pattern is the
       same as that used for filename generation; see the section  `Filename  Generation'.   Note
       that  these patterns, along with the replacement text of any substitutions, are themselves
       subject to parameter expansion, command substitution, and arithmetic expansion.	In  addi-
       tion to the following operations, the colon modifiers described in the section `Modifiers'
       in the section `History Expansion' can be applied:  for example, ${i:s/foo/bar/}  performs
       string substitution on the expansion of parameter $i.

	      The  value,  if any, of the parameter name is substituted.  The braces are required
	      if the expansion is to be followed by a letter, digit, or underscore that is not to
	      be  interpreted  as part of name.  In addition, more complicated forms of substitu-
	      tion usually require the braces to be present; exceptions, which only apply if  the
	      option KSH_ARRAYS is not set, are a single subscript or any colon modifiers appear-
	      ing after the name, or any of the characters `^', `=', `~', `#'  or  `+'	appearing
	      before the name, all of which work with or without braces.

	      If name is an array parameter, and the KSH_ARRAYS option is not set, then the value
	      of each element of name is substituted,  one  element  per  word.   Otherwise,  the
	      expansion  results  in one word only; with KSH_ARRAYS, this is the first element of
	      an array.  No field splitting is done on the result unless the SH_WORD_SPLIT option
	      is set.

	      If name is the name of a set parameter `1' is substituted, otherwise `0' is substi-

	      If name is set and is non-null then  substitute  its  value;  otherwise  substitute
	      word. If name is missing, substitute word.

	      In  the  first form, if name is unset or is null then set it to word; in the second
	      form, unconditionally set name to word.  In both forms, the value of the	parameter
	      is then substituted.

	      If name is set and is non-null then substitute its value; otherwise, print word and
	      exit from the shell.  Interactive shells instead return to the prompt.  If word  is
	      omitted, then a standard message is printed.

	      If name is set and is non-null then substitute word; otherwise substitute nothing.

       If  the	colon  is  omitted from one of the above expressions containing a colon, then the
       shell only checks whether name is set, not whether its value is null.

       In the following expressions, when name is an array and the substitution is not quoted, or
       if  the `(@)' flag or the name[@] syntax is used, matching and replacement is performed on
       each array element separately.

	      If the pattern matches the beginning of the value  of  name,  then  substitute  the
	      value  of  name  with  the  matched portion deleted; otherwise, just substitute the
	      value of name.  In the first form, the smallest matching pattern is  preferred;  in
	      the second form, the largest matching pattern is preferred.

	      If  the  pattern matches the end of the value of name, then substitute the value of
	      name with the matched portion deleted; otherwise,  just  substitute  the	value  of
	      name.  In the first form, the smallest matching pattern is preferred; in the second
	      form, the largest matching pattern is preferred.

	      If the pattern matches the value of name, then substitute the empty string;  other-
	      wise,  just  substitute  the value of name.  If name is an array the matching array
	      elements are removed (use the `(M)' flag to remove the non-matched elements).

	      Replace the longest possible match of pattern in the expansion of parameter name by
	      string  repl.   The  first form replaces just the first occurrence, the second form
	      all occurrences.	Both pattern and repl are subject to double-quoted  substitution,
	      so  that	expressions  like  ${name/$opat/$npat} will work, but note the usual rule
	      that pattern characters in $opat are not treated specially unless either the option
	      GLOB_SUBST is set, or $opat is instead substituted as ${~opat}.

	      The pattern may begin with a `#', in which case the pattern must match at the start
	      of the string, or `%', in which case it must match at the end of the  string.   The
	      repl  may  be an empty string, in which case the final `/' may also be omitted.  To
	      quote the final `/' in other cases it should be preceded by two backslashes  (i.e.,
	      a  quoted  backslash); this is not necessary if the `/' occurs inside a substituted
	      parameter.  Note also that the `#' and `%' are not active if they  occur	inside	a
	      substituted parameter, even at the start.

	      The  first  `/' may be preceded by a `:', in which case the match will only succeed
	      if it matches the entire word.  Note also the effect  of	the  I	and  S	parameter
	      expansion flags below; however, the flags M, R, B, E and N are not useful.

	      For example,

		     foo="twinkle twinkle little star" sub="t*e" rep="spy"
		     print ${foo//${~sub}/$rep}
		     print ${(S)foo//${~sub}/$rep}

	      Here,  the  `~' ensures that the text of $sub is treated as a pattern rather than a
	      plain string.  In the first case, the longest match for t*e is substituted and  the
	      result  is `spy star', while in the second case, the shortest matches are taken and
	      the result is `spy spy lispy star'.

	      If spec is one of the above substitutions, substitute the length in  characters  of
	      the  result  instead of the result itself.  If spec is an array expression, substi-
	      tute the number of elements of the result.  Note that `^',  `=',	and  `~',  below,
	      must appear to the left of `#' when these forms are combined.

	      Turn  on	the RC_EXPAND_PARAM option for the evaluation of spec; if the `^' is dou-
	      bled, turn it off.   When  this  option  is  set,  array	expansions  of	the  form
	      foo${xx}bar,  where  the	parameter  xx  is  set	to  (a b c), are substituted with
	      `fooabar foobbar foocbar' instead of the default `fooa b cbar'.

	      Internally, each such expansion is converted into the  equivalent  list  for  brace
	      expansion.   E.g.,  ${^var}  becomes  {$var[1],$var[2],...},  and  is  processed as
	      described in the section `Brace Expansion' below.  If word  splitting  is  also  in
	      effect the $var[N] may themselves be split into different list elements.

	      Perform  word  splitting using the rules for SH_WORD_SPLIT during the evaluation of
	      spec, but regardless of whether the parameter appears in double quotes; if the  `='
	      is  doubled,  turn it off.  This forces parameter expansions to be split into sepa-
	      rate words before substitution, using IFS as a delimiter.  This is done by  default
	      in most other shells.

	      Note  that  splitting is applied to word in the assignment forms of spec before the
	      assignment to name is performed.	This affects the result of array assignments with
	      the A flag.

	      Turn  on	the  GLOB_SUBST option for the evaluation of spec; if the `~' is doubled,
	      turn it off.  When this option is set, the string resulting from the expansion will
	      be  interpreted  as a pattern anywhere that is possible, such as in filename expan-
	      sion and filename generation and pattern-matching contexts like the right hand side
	      of the `=' and `!=' operators in conditions.

       If  a  ${...}  type  parameter expression or a $(...) type command substitution is used in
       place of name above, it is expanded first and the result is used as if it were  the  value
       of  name.   Thus it is possible to perform nested operations:  ${${foo#head}%tail} substi-
       tutes the value of $foo with both `head' and `tail' deleted.   The  form  with  $(...)  is
       often  useful  in combination with the flags described next; see the examples below.  Each
       name or nested ${...} in a parameter expansion may also be followed by a subscript expres-
       sion as described in Array Parameters in zshparam(1).

       Note  that double quotes may appear around nested expressions, in which case only the part
       inside is treated as quoted; for example, ${(f)"$(foo)"} quotes the result of $(foo),  but
       the  flag `(f)' (see below) is applied using the rules for unquoted expansions.	Note fur-
       ther that quotes are themselves nested in this context; for example, in "${(@f)"$(foo)"}",
       there  are two sets of quotes, one surrounding the whole expression, the other (redundant)
       surrounding the $(foo) as before.

   Parameter Expansion Flags
       If the opening brace is directly followed by an opening parenthesis, the string up to  the
       matching closing parenthesis will be taken as a list of flags.  In cases where repeating a
       flag is meaningful, the repetitions need not be consecutive; for example, `(q%q%q)'  means
       the same thing as the more readable `(%%qqq)'.  The following flags are supported:

       %      Expand  all  % escapes in the resulting words in the same way as in in prompts (see
	      the section `Prompt Expansion'). If this flag is given twice, full prompt expansion
	      is  done	on  the  resulting words, depending on the setting of the PROMPT_PERCENT,
	      PROMPT_SUBST and PROMPT_BANG options.

       @      In double quotes, array elements are put into separate words.  E.g.,  `"${(@)foo}"'
	      is  equivalent  to  `"${foo[@]}"'  and `"${(@)foo[1,2]}"' is the same as `"$foo[1]"
	      "$foo[2]"'.  This is distinct from field splitting by the the  f,  s  or	z  flags,
	      which still applies within each array element.

       A      Create  an  array parameter with `${...=...}', `${...:=...}' or `${...::=...}'.  If
	      this flag is repeated (as in `AA'), create an associative array parameter.  Assign-
	      ment  is	made before sorting or padding.  The name part may be a subscripted range
	      for ordinary arrays; the word part must be converted to an array,  for  example  by
	      using  `${(AA)=name=...}' to activate field splitting, when creating an associative

       c      With ${#name}, count the total number of characters in an array, as if the elements
	      were concatenated with spaces between them.

       C      Capitalize  the  resulting  words.   `Words'  in	this  case refers to sequences of
	      alphanumeric characters separated by non-alphanumerics, not to  words  that  result
	      from field splitting.

       e      Perform  parameter  expansion, command substitution and arithmetic expansion on the
	      result. Such expansions can be nested but too deep recursion may have unpredictable

       f      Split the result of the expansion to lines. This is a shorthand for `ps:\n:'.

       F      Join  the  words of arrays together using newline as a separator.  This is a short-
	      hand for `pj:\n:'.

       i      With o or O, sort case-independently.

       k      If name refers to an associative array, substitute the keys (element names)  rather
	      than the values of the elements.	Used with subscripts (including ordinary arrays),
	      force indices or keys to be substituted even if the subscript form refers  to  val-
	      ues.  However, this flag may not be combined with subscript ranges.

       L      Convert all letters in the result to lower case.

       o      Sort the resulting words in ascending order.

       O      Sort the resulting words in descending order.

       P      This  forces the value of the parameter name to be interpreted as a further parame-
	      ter name, whose value will be used where appropriate. If used with a nested parame-
	      ter  or  command substitution, the result of that will be taken as a parameter name
	      in the same way.	For example, if you have `foo=bar'  and  `bar=baz',  the  strings
	      ${(P)foo}, ${(P)${foo}}, and ${(P)$(echo bar)} will be expanded to `baz'.

       q      Quote  the  resulting  words  with  backslashes.	If  this flag is given twice, the
	      resulting words are quoted in single quotes and if it is	given  three  times,  the
	      words  are quoted in double quotes. If it is given four times, the words are quoted
	      in single quotes preceded by a $.

       Q      Remove one level of quotes from the resulting words.

       t      Use a string describing the type of the parameter where the value of the	parameter
	      would  usually appear. This string consists of keywords separated by hyphens (`-').
	      The first keyword in the string describes the main type, it can be one of `scalar',
	      `array',	`integer', `float' or `association'. The other keywords describe the type
	      in more detail:

	      local  for local parameters

	      left   for left justified parameters

		     for right justified parameters with leading blanks

		     for right justified parameters with leading zeros

	      lower  for parameters whose value is  converted  to  all	lower  case  when  it  is

	      upper  for  parameters  whose  value  is	converted  to  all  upper case when it is

		     for readonly parameters

	      tag    for tagged parameters

	      export for exported parameters

	      unique for arrays which keep only the first occurrence of duplicated values

	      hide   for parameters with the `hide' flag

		     for special parameters defined by the shell

       U      Convert all letters in the result to upper case.

       v      Used with k, substitute (as two consecutive words) both the key and  the	value  of
	      each  associative  array element.  Used with subscripts, force values to be substi-
	      tuted even if the subscript form refers to indices or keys.

       V      Make any special characters in the resulting words visible.

       w      With ${#name}, count words in arrays or strings; the s flag may be used  to  set	a
	      word delimiter.

       W      Similar  to  w with the difference that empty words between repeated delimiters are
	      also counted.

       X      With this flag parsing errors occurring with the Q  and  e  flags  or  the  pattern
	      matching	forms  such  as `${name#pattern}' are reported. Without the flag they are
	      silently ignored.

       z      Split the result of the expansion into words using shell parsing to find the words,
	      i.e. taking into account any quoting in the value.

	      Note  that this is done very late, as for the `(s)' flag. So to access single words
	      in the result, one has to use nested expansions as in `${${(z)foo}[2]}'.	Likewise,
	      to remove the quotes in the resulting words one would do: `${(Q)${(z)foo}}'.

       The  following flags (except p) are followed by one or more arguments as shown.	Any char-
       acter, or the matching pairs `(...)', `{...}', `[...]', or `<...>', may be used	in  place
       of  a  colon  as  delimiters,  but  note  that when a flag takes more than one argument, a
       matched pair of delimiters must surround each argument.

       p      Recognize the same escape sequences as the print builtin in string arguments to any
	      of the flags described below.

	      Join  the  words	of  arrays  together using string as a separator.  Note that this
	      occurs before field splitting by the SH_WORD_SPLIT option.

	      Pad the resulting words on the left.  Each word will be truncated if  required  and
	      placed  in a field expr characters wide.	The space to the left will be filled with
	      string1 (concatenated as often as needed) or spaces if string1 is  not  given.   If
	      both  string1  and  string2 are given, this string is inserted once directly to the
	      left of each word, before padding.

	      As l, but pad the words on the right and insert string2 on the right.

	      Force field splitting (see the option SH_WORD_SPLIT) at the separator string.  Note
	      that  a string of two or more characters means all must all match in sequence; this
	      differs from the treatment of two or more characters in the IFS parameter.

       The following flags are meaningful with the ${...#...} or ${...%...} forms.  The S  and	I
       flags may also be used with the ${.../...} forms.

       S      Search  substrings  as  well as beginnings or ends; with # start from the beginning
	      and with % start from the end of the string.  With substitution via  ${.../...}  or
	      ${...//...},  specifies  non-greedy matching, i.e. that the shortest instead of the
	      longest match should be replaced.

	      Search the exprth match (where expr evaluates to a number).  This only applies when
	      searching  for  substrings,  either  with  the S flag, or with ${.../...} (only the
	      exprth match is substituted) or ${...//...} (all matches from  the  exprth  on  are
	      substituted).  The default is to take the first match.

	      The exprth match is counted such that there is either one or zero matches from each
	      starting position in the string, although for global substitution matches  overlap-
	      ping previous replacements are ignored.  With the ${...%...} and ${...%%...} forms,
	      the starting position for the match moves backwards  from  the  end  as  the  index
	      increases, while with the other forms it moves forward from the start.

	      Hence with the string
		     which switch is the right switch for Ipswich?
	      substitutions  of  the  form ${(SI:N:)string#w*ch} as N increases from 1 will match
	      and remove `which', `witch', `witch' and `wich'; the form using `##' will match and
	      remove  `which  switch is the right switch for Ipswich', `witch is the right switch
	      for Ipswich', `witch for Ipswich' and `wich'. The form using `%'	will  remove  the
	      same  matches as for `#', but in reverse order, and the form using `%%' will remove
	      the same matches as for `##' in reverse order.

       B      Include the index of the beginning of the match in the result.

       E      Include the index of the end of the match in the result.

       M      Include the matched portion in the result.

       N      Include the length of the match in the result.

       R      Include the unmatched portion in the result (the Rest).

       Here is a summary of the rules for substitution; this  assumes  that  braces  are  present
       around  the  substitution,  i.e.  ${...}.  Some particular examples are given below.  Note
       that the Zsh Development Group accepts no responsibility for any brain  damage  which  may
       occur during the reading of the following rules.

       1. Nested Substitution
	      If  multiple  nested  ${...}  forms are present, substitution is performed from the
	      inside outwards.	At each level, the substitution takes account of whether the cur-
	      rent  value  is  a  scalar or an array, whether the whole substitution is in double
	      quotes, and what flags are supplied to the current level of substitution,  just  as
	      if  the nested substitution were the outermost.  The flags are not propagated up to
	      enclosing substitutions; the nested substitution will return either a scalar or  an
	      array as determined by the flags, possibly adjusted for quoting.	All the following
	      steps take place where applicable at all levels of substitution.	Note that, unless
	      the `(P)' flag is present, the flags and any subscripts apply directly to the value
	      of the nested substitution; for example, the expansion  ${${foo}}  behaves  exactly
	      the same as ${foo}.

       2. Parameter Subscripting
	      If  the value is a raw parameter reference with a subscript, such as ${var[3]}, the
	      effect of subscripting is applied directly to the parameter.  Subscripts are evalu-
	      ated  left  to  right;  subsequent  subscripts  apply  to the scalar or array value
	      yielded by the previous subscript.  Thus if var is an array,  ${var[1][2]}  is  the
	      second  character  of  the  first word, but ${var[2,4][2]} is the entire third word
	      (the second word of the range of words two through four  of  the	original  array).
	      Any number of subscripts may appear.

       3. Parameter Name Replacement
	      The  effect  of any (P) flag, which treats the value so far as a parameter name and
	      replaces it with the corresponding value, is applied.

       4. Double-Quoted Joining
	      If the value after this process is an array, and the substitution appears in double
	      quotes, and no (@) flag is present at the current level, the words of the value are
	      joined with the first character of the parameter $IFS, by default a space,  between
	      each  word (single word arrays are not modified).  If the (j) flag is present, that
	      is used for joining instead of $IFS.

       5. Nested Subscripting
	      Any remaining subscripts (i.e. of a nested  substitution)  are  evaluated  at  this
	      point,  based  on  whether the value is an array or a scalar.  As with 2., multiple
	      subscripts  can  appear.	 Note  that  ${foo[2,4][2]}   is   thus   equivalent   to
	      ${${foo[2,4]}[2]}  and  also  to	"${${(@)foo[2,4]}[2]}"	(the  nested substitution
	      returns an array in both cases), but not to "${${foo[2,4]}[2]}" (the nested substi-
	      tution returns a scalar because of the quotes).

       6. Modifiers
	      Any  modifiers, as specified by a trailing `#', `%', `/' (possibly doubled) or by a
	      set of modifiers of the form :... (see the section `Modifiers' in the section `His-
	      tory Expansion'), are applied to the words of the value at this level.

       7. Forced Joining
	      If  the  `(j)' flag is present, or no `(j)' flag is present but the string is to be
	      split as given by rules 8. or 9., and joining did not take place at  step  4.,  any
	      words  in the value are joined together using the given string or the first charac-
	      ter of $IFS if none.  Note that the `(F)' flag implicitly  supplies  a  string  for
	      joining in this manner.

       8. Forced Splitting
	      If  one  of  the	`(s)', `(f)' or `(z)' flags are present, or the `=' specifier was
	      present (e.g. ${=var}), the word is split on occurrences of the  specified  string,
	      or (for = with neither of the two flags present) any of the characters in $IFS.

       9. Shell Word Splitting
	      If  no  `(s)',  `(f)'  or  `=' was given, but the word is not quoted and the option
	      SH_WORD_SPLIT is set, the word is split on occurrences of any of the characters  in
	      $IFS.  Note this step, too, takes place at all levels of a nested substitution.

       10. Re-Evaluation
	      Any `(e)' flag is applied to the value, forcing it to be re-examined for new param-
	      eter substitutions, but also for command and arithmetic substitutions.

       11. Padding
	      Any padding of the value by the `(l.fill.)' or `(r.fill.)' flags is applied.

       12. Semantic Joining
	      In contexts where expansion semantics requires a single word to result,  all  words
	      are  rejoined  with  the first character of IFS between.	So in `${(P)${(f)lines}}'
	      the value of ${lines} is split at newlines, but then must be  joined  again  before
	      the P flag can be applied.

	      If a single word is not required, this rule is skipped.

       The  flag  f  is  useful to split a double-quoted substitution line by line.  For example,
       ${(f)"$(<file)"} substitutes the contents of file divided so that each line is an  element
       of the resulting array.	Compare this with the effect of $(<file) alone, which divides the
       file up by words, or the same inside double quotes, which makes the entire content of  the
       file a single string.

       The  following  illustrates  the rules for nested parameter expansions.	Suppose that $foo
       contains the array (bar baz):

	      This produces the result b.  First, the inner substitution "${foo}", which  has  no
	      array  (@)  flag,  produces a single word result "bar baz".  The outer substitution
	      "${(@)...[1]}" detects that this is a scalar, so that (despite the `(@)' flag)  the
	      subscript picks the first character.

	      This  produces  the result `bar'.  In this case, the inner substitution "${(@)foo}"
	      produces the array `(bar baz)'.  The outer substitution  "${...[1]}"  detects  that
	      this  is	an  array  and	picks the first word.  This is similar to the simple case

       As an example of the rules for word splitting and joining, suppose $foo contains the array
       `(ax1 bx1)'.  Then

	      produces the words `a', `1 b' and `1'.

	      produces `a', `1', `b' and `1'.

	      produces `a' and ` b' (note the extra space).  As substitution occurs before either
	      joining or splitting, the operation  first generates the modified  array	(ax  bx),
	      which  is  joined  to  give  "ax bx", and then split to give `a', ` b' and `'.  The
	      final empty string will then be elided, as it is not in double quotes.

       A command enclosed in parentheses preceded by a dollar sign, like `$(...)', or quoted with
       grave  accents, like ``...`', is replaced with its standard output, with any trailing new-
       lines deleted.  If the substitution is not enclosed in double quotes, the output is broken
       into  words using the IFS parameter.  The substitution `$(cat foo)' may be replaced by the
       equivalent but faster `$(<foo)'.  In either case, if the option	GLOB_SUBST  is	set,  the
       output is eligible for filename generation.

       A  string  of  the form `$[exp]' or `$((exp))' is substituted with the value of the arith-
       metic expression exp.  exp is subjected to parameter expansion, command	substitution  and
       arithmetic expansion before it is evaluated.  See the section `Arithmetic Evaluation'.

       A  string  of  the form `foo{xx,yy,zz}bar' is expanded to the individual words `fooxxbar',
       `fooyybar' and `foozzbar'.  Left-to-right order	is  preserved.	 This  construct  may  be
       nested.	Commas may be quoted in order to include them literally in a word.

       An  expression  of the form `{n1..n2}', where n1 and n2 are integers, is expanded to every
       number between n1 and n2 inclusive.  If either number begins with a zero, all the  result-
       ing  numbers will be padded with leading zeroes to that minimum width.  If the numbers are
       in decreasing order the resulting sequence will also be in decreasing order.

       If a brace expression matches none of the above forms, it is left  unchanged,  unless  the
       BRACE_CCL  option is set.  In that case, it is expanded to a sorted list of the individual
       characters between the braces, in the manner of a search set.  `-' is treated specially as
       in a search set, but `^' or `!' as the first character is treated normally.

       Note  that  brace  expansion  is not part of filename generation (globbing); an expression
       such as */{foo,bar} is split into two separate words */foo and */bar before filename  gen-
       eration	takes  place.	In  particular,  note that this is liable to produce a `no match'
       error if either of the two expressions does not match;  this  is  to  be  contrasted  with
       */(foo|bar), which is treated as a single pattern but otherwise has similar effects.

       Each  word is checked to see if it begins with an unquoted `~'.	If it does, then the word
       up to a `/', or the end of the word if there is no `/', is checked to see  if  it  can  be
       substituted  in	one of the ways described here.  If so, then the `~' and the checked por-
       tion are replaced with the appropriate substitute value.

       A `~' by itself is replaced by the value of $HOME.  A `~' followed by a `+' or  a  `-'  is
       replaced by the value of $PWD or $OLDPWD, respectively.

       A  `~' followed by a number is replaced by the directory at that position in the directory
       stack.  `~0' is equivalent to `~+', and `~1' is the top of the stack.  `~+' followed by	a
       number  is  replaced  by  the directory at that position in the directory stack.  `~+0' is
       equivalent to `~+', and `~+1' is the top of the stack.	`~-'  followed	by  a  number  is
       replaced  by the directory that many positions from the bottom of the stack.  `~-0' is the
       bottom of the stack.  The PUSHD_MINUS option exchanges the effects of `~+' and `~-'  where
       they are followed by a number.

       A  `~'  followed  by  anything  not already covered is looked up as a named directory, and
       replaced by the value of that named directory if found.	Named directories  are	typically
       home  directories for users on the system.  They may also be defined if the text after the
       `~' is the name of a string shell parameter whose value begins with a  `/'.   It  is  also
       possible to define directory names using the -d option to the hash builtin.

       In  certain  circumstances  (in	prompts, for instance), when the shell prints a path, the
       path is checked to see if it has a named directory as its prefix.  If so, then the  prefix
       portion is replaced with a `~' followed by the name of the directory.  The shortest way of
       referring to the directory is used, with ties broken in favour of using a named directory,
       except when the directory is / itself.  The parameters $PWD and $OLDPWD are never abbrevi-
       ated in this fashion.

       If a word begins with an unquoted `=' and the EQUALS option is set, the remainder  of  the
       word  is  taken	as the name of a command or alias.  If a command exists by that name, the
       word is replaced by the full pathname of the command.  If an alias exists  by  that  name,
       the word is replaced with the text of the alias.

       Filename  expansion is performed on the right hand side of a parameter assignment, includ-
       ing those appearing after commands of the typeset family.  In this case,  the  right  hand
       side  will  be  treated	as a colon-separated list in the manner of the PATH parameter, so
       that a `~' or an `=' following a `:' is eligible for expansion.	All such behaviour can be
       disabled  by quoting the `~', the `=', or the whole expression (but not simply the colon);
       the EQUALS option is also respected.

       If the option MAGIC_EQUAL_SUBST is set, any unquoted shell argument in the  form  `identi-
       fier=expression'  becomes  eligible  for file expansion as described in the previous para-
       graph.  Quoting the first `=' also inhibits this.

       If a word contains an unquoted instance of one of the characters `*', `(', `|', `<',  `[',
       or  `?',  it  is  regarded as a pattern for filename generation, unless the GLOB option is
       unset.  If the EXTENDED_GLOB option is set, the `^' and `#' characters also denote a  pat-
       tern; otherwise they are not treated specially by the shell.

       The word is replaced with a list of sorted filenames that match the pattern.  If no match-
       ing pattern is found, the shell gives an error message, unless  the  NULL_GLOB  option  is
       set,  in  which	case the word is deleted; or unless the NOMATCH option is unset, in which
       case the word is left unchanged.

       In filename generation, the character `/' must be matched explicitly; also, a `.' must  be
       matched	explicitly  at	the  beginning	of a pattern or after a `/', unless the GLOB_DOTS
       option is set.  No filename generation pattern matches the files `.' or	`..'.	In  other
       instances of pattern matching, the `/' and `.' are not treated specially.

   Glob Operators
       *      Matches any string, including the null string.

       ?      Matches any character.

       [...]  Matches  any  of the enclosed characters.  Ranges of characters can be specified by
	      separating two characters by a `-'.  A `-' or `]' may be matched by including it as
	      the  first  character in the list.  There are also several named classes of charac-
	      ters, in the form `[:name:]' with the  following	meanings:   `[:alnum:]'  alphanu-
	      meric,  `[:alpha:]' alphabetic, `[:blank:]' space or tab, `[:cntrl:]' control char-
	      acter, `[:digit:]' decimal digit, `[:graph:]'  printable	character  except  white-
	      space,  `[:lower:]'  lowercase letter, `[:print:]' printable character, `[:punct:]'
	      printable character neither alphanumeric	nor  whitespace,  `[:space:]'  whitespace
	      character, `[:upper:]' uppercase letter, `[:xdigit:]' hexadecimal digit.	These use
	      the macros provided by the operating system to test for the given character  combi-
	      nations, including any modifications due to local language settings:  see ctype(3).
	      Note that the square brackets are additional to those enclosing the  whole  set  of
	      characters,  so to test for a single alphanumeric character you need `[[:alnum:]]'.
	      Named character sets can be used alongside other types, e.g. `[[:alpha:]0-9]'.

       [!...] Like [...], except that it matches any character which is not in the given set.

	      Matches any number in the range x to y, inclusive.  Either of the  numbers  may  be
	      omitted  to  make  the  range open-ended; hence `<->' matches any number.  To match
	      individual digits, the [...] form is more efficient.

	      Be careful when using other wildcards adjacent to patterns of this form; for  exam-
	      ple,  <0-9>*  will actually match any number whatsoever at the start of the string,
	      since the `<0-9>' will match the first digit, and the `*' will  match  any  others.
	      This is a trap for the unwary, but is in fact an inevitable consequence of the rule
	      that  the  longest  possible  match   always   succeeds.	  Expressions	such   as
	      `<0-9>[^[:digit:]]*' can be used instead.

       (...)  Matches  the  enclosed pattern.  This is used for grouping.  If the KSH_GLOB option
	      is set, then a `@', `*', `+', `?' or `!' immediately preceding the `('  is  treated
	      specially,  as  detailed	below.	The option SH_GLOB prevents bare parentheses from
	      being used in this way, though the KSH_GLOB option is still available.

	      Note that grouping cannot extend over multiple directories: it is an error to  have
	      a  `/' within a group (this only applies for patterns used in filename generation).
	      There is one exception:  a group of the form (pat/)# appearing as a  complete  path
	      segment  can  match  a sequence of directories.  For example, foo/(a*/)#bar matches
	      foo/bar, foo/any/bar, foo/any/anyother/bar, and so on.

       x|y    Matches either x or y.  This operator has lower precedence than any other.  The `|'
	      character must be within parentheses, to avoid interpretation as a pipeline.

       ^x     (Requires  EXTENDED_GLOB	to be set.)  Matches anything except the pattern x.  This
	      has a higher precedence than `/', so `^foo/bar'  will  search  directories  in  `.'
	      except `./foo' for a file named `bar'.

       x~y    (Requires  EXTENDED_GLOB to be set.)  Match anything that matches the pattern x but
	      does not match y.  This has lower precedence  than  any  operator  except  `|',  so
	      `*/*~foo/bar' will search for all files in all directories in `.'  and then exclude
	      `foo/bar' if there was  such  a  match.	Multiple  patterns  can  be  excluded  by
	      `foo~bar~baz'.  In the exclusion pattern (y), `/' and `.' are not treated specially
	      the way they usually are in globbing.

       x#     (Requires EXTENDED_GLOB to be set.)  Matches zero or more occurrences of	the  pat-
	      tern  x.	This operator has high precedence; `12#' is equivalent to `1(2#)', rather
	      than `(12)#'.  It is an error for an unquoted `#' to follow something which  cannot
	      be  repeated; this includes an empty string, a pattern already followed by `##', or
	      parentheses when part of a KSH_GLOB pattern (for example, `!(foo)#' is invalid  and
	      must be replaced by `*(!(foo))').

       x##    (Requires EXTENDED_GLOB to be set.)  Matches one or more occurrences of the pattern
	      x.  This operator has high precedence; `12##' is	equivalent  to	`1(2##)',  rather
	      than `(12)##'.  No more than two active `#' characters may appear together.

   ksh-like Glob Operators
       If  the	KSH_GLOB option is set, the effects of parentheses can be modified by a preceding
       `@', `*', `+', `?' or `!'.  This character need not be unquoted to have	special  effects,
       but the `(' must be.

       @(...) Match the pattern in the parentheses.  (Like `(...)'.)

       *(...) Match any number of occurrences.	(Like `(...)#'.)

       +(...) Match at least one occurrence.  (Like `(...)##'.)

       ?(...) Match zero or one occurrence.  (Like `(|...)'.)

       !(...) Match anything but the expression in parentheses.  (Like `(^(...))'.)

       The  precedence of the operators given above is (highest) `^', `/', `~', `|' (lowest); the
       remaining operators are simply treated from left to right as part of a  string,	with  `#'
       and `##' applying to the shortest possible preceding unit (i.e. a character, `?', `[...]',
       `<...>', or a parenthesised expression).  As mentioned above, a `/' used  as  a	directory
       separator  may  not appear inside parentheses, while a `|' must do so; in patterns used in
       other contexts than filename generation (for example, in case statements and tests  within
       `[[...]]'),  a  `/' is not special; and `/' is also not special after a `~' appearing out-
       side parentheses in a filename pattern.

   Globbing Flags
       There are various flags which affect any text to their right up to the end of the  enclos-
       ing  group  or  to the end of the pattern; they require the EXTENDED_GLOB option. All take
       the form (#X) where X may have one of the following forms:

       i      Case insensitive:  upper or lower case characters in the	pattern  match	upper  or
	      lower case characters.

       l      Lower  case  characters  in the pattern match upper or lower case characters; upper
	      case characters in the pattern still only match upper case characters.

       I      Case sensitive:  locally negates the effect of i or l from that point on.

       b      Activate backreferences for parenthesised groups in the pattern; this does not work
	      in  filename  generation.   When	a  pattern  with  a  set of active parentheses is
	      matched, the strings matched by the groups are stored  in  the  array  $match,  the
	      indices  of  the beginning of the matched parentheses in the array $mbegin, and the
	      indices of the end in the array $mend, with the first element of each array  corre-
	      sponding	to the first parenthesised group, and so on.  These arrays are not other-
	      wise special to the shell.  The indices use the same convention as  does	parameter
	      substitution,  so that elements of $mend and $mbegin may be used in subscripts; the
	      KSH_ARRAYS option is respected.  Sets of globbing flags are not  considered  paren-
	      thesised groups; only the first nine active parentheses can be referenced.

	      For example,

		     foo="a string with a message"
		     if [[ $foo = (a|an)' '(#b)(*)' '* ]]; then
		       print ${foo[$mbegin[1],$mend[1]]}

	      prints  `string  with  a'.   Note that the first parenthesis is before the (#b) and
	      does not create a backreference.

	      Backreferences work with all forms of pattern matching other than filename  genera-
	      tion,  but  note	that  when  performing	matches  on  an  entire  array,  such  as
	      ${array#pattern}, or a global substitution, such as  ${param//pat/repl},	only  the
	      data for the last match remains available.  In the case of global replacements this
	      may still be useful.  See the example for the m flag below.

	      The numbering of backreferences strictly follows the order of the opening parenthe-
	      ses  from  left to right in the pattern string, although sets of parentheses may be
	      nested.  There are special rules for parentheses followed by `#' or `##'.  Only the
	      last match of the parenthesis is remembered: for example, in `[[ abab = (#b)([ab])#
	      ]]', only the final `b' is stored in match[1].  Thus extra parentheses may be  nec-
	      essary  to  match  the complete segment: for example, use `X((ab|cd)#)Y' to match a
	      whole string of either `ab' or `cd'  between  `X'  and  `Y',  using  the	value  of
	      $match[1] rather than $match[2].

	      If  the  match  fails none of the parameters is altered, so in some cases it may be
	      necessary to initialise them beforehand.	If some of  the  backreferences  fail  to
	      match --- which happens if they are in an alternate branch which fails to match, or
	      if they are followed by # and matched zero times --- then the matched string is set
	      to the empty string, and the start and end indices are set to -1.

	      Pattern matching with backreferences is slightly slower than without.

       B      Deactivate backreferences, negating the effect of the b flag from that point on.

       m      Set  references to the match data for the entire string matched; this is similar to
	      backreferencing and does not work in filename generation.   The  flag  must  be  in
	      effect at the end of the pattern, i.e. not local to a group. The parameters $MATCH,
	      $MBEGIN and $MEND will be set to the string matched  and	to  the  indices  of  the
	      beginning  and  end  of the string, respectively.  This is most useful in parameter
	      substitutions, as otherwise the string matched is obvious.

	      For example,

		     arr=(veldt jynx grimps waqf zho buck)
		     print ${arr//(#m)[aeiou]/${(U)MATCH}}

	      forces all the matches (i.e. all	vowels)  into  uppercase,  printing  `vEldt  jynx
	      grImps wAqf zhO bUck'.

	      Unlike  backreferences, there is no speed penalty for using match references, other
	      than the extra substitutions required for the replacement strings in cases such  as
	      the example shown.

       M      Deactivate the m flag, hence no references to match data will be created.

       anum   Approximate  matching: num errors are allowed in the string matched by the pattern.
	      The rules for this are described in the next subsection.

       s, e   Unlike the other flags, these have only a local effect, and each must appear on its
	      own:  `(#s)' and `(#e)' are the only valid forms.  The `(#s)' flag succeeds only at
	      the start of the test string, and the `(#e)' flag succeeds only at the end  of  the
	      test  string; they correspond to `^' and `$' in standard regular expressions.  They
	      are useful for matching path segments in patterns other than those in filename gen-
	      eration  (where  path  segments  are in any case treated separately).  For example,
	      `*((#s)|/)test((#e)|/)*' matches a path segment `test'  in  any  of  the	following
	      strings: test, test/at/start, at/end/test, in/test/middle.

	      Another  use  is in parameter substitution; for example `${array/(#s)A*Z(#e)}' will
	      remove only elements of an array which match the complete pattern `A*Z'.	There are
	      other  ways  of performing many operations of this type, however the combination of
	      the substitution operations `/' and `//' with the `(#s)' and `(#e)' flags  provides
	      a single simple and memorable method.

	      Note that assertions of the form `(^(#s))' also work, i.e. match anywhere except at
	      the  start  of  the  string,  although  this  actually  means  `anything	except	a
	      zero-length  portion  at	the  start of the string'; you need to use `(""~(#s))' to
	      match a zero-length portion of the string not at the start.

       For example, the test string fooxx can be matched by the pattern  (#i)FOOXX,  but  not  by
       (#l)FOOXX,  (#i)FOO(#I)XX or ((#i)FOOX)X.  The string (#ia2)readme specifies case-insensi-
       tive matching of readme with up to two errors.

       When using the ksh syntax for grouping both KSH_GLOB and EXTENDED_GLOB must be set and the
       left  parenthesis should be preceded by @.  Note also that the flags do not affect letters
       inside [...] groups, in other  words  (#i)[a-z]	still  matches	only  lowercase  letters.
       Finally,  note  that when examining whole paths case-insensitively every directory must be
       searched for all files which match, so that a pattern  of  the  form  (#i)/foo/bar/...  is
       potentially slow.

   Approximate Matching
       When  matching  approximately,  the  shell keeps a count of the errors found, which cannot
       exceed the number specified in the (#anum) flags.  Four types of error are recognised:

       1.     Different characters, as in fooxbar and fooybar.

       2.     Transposition of characters, as in banana and abnana.

       3.     A character missing in the target string, as  with  the  pattern	road  and  target
	      string rod.

       4.     An extra character appearing in the target string, as with stove and strove.

       Thus,  the  pattern  (#a3)abcd  matches dcba, with the errors occurring by using the first
       rule twice and the second once, grouping the string as [d][cb][a] and [a][bc][d].

       Non-literal parts of the pattern must match exactly,  including	characters  in	character
       ranges:	hence  (#a1)???   matches  strings of length four, by applying rule 4 to an empty
       part of the pattern, but not strings of length two, since all the  ?  must  match.   Other
       characters  which  must	match exactly are initial dots in filenames (unless the GLOB_DOTS
       option is set), and all slashes in filenames, so that a/bc is two errors  from  ab/c  (the
       slash  cannot  be transposed with another character).  Similarly, errors are counted sepa-
       rately for non-contiguous strings in the pattern, so that (ab|cd)ef  is	two  errors  from

       When  using  exclusion  via the ~ operator, approximate matching is treated entirely sepa-
       rately for the excluded part and must be activated separately.  Thus,  (#a1)README~READ_ME
       matches READ.ME but not READ_ME, as the trailing READ_ME is matched without approximation.
       However, (#a1)README~(#a1)READ_ME does not match any pattern of the form  READ?ME  as  all
       such forms are now excluded.

       Apart  from exclusions, there is only one overall error count; however, the maximum errors
       allowed may be altered locally, and this can  be  delimited  by	grouping.   For  example,
       (#a1)cat((#a0)dog)fox  allows  one error in total, which may not occur in the dog section,
       and the pattern (#a1)cat(#a0)dog(#a1)fox is equivalent.	Note that the point at	which  an
       error is first found is the crucial one for establishing whether to use approximation; for
       example, (#a1)abc(#a0)xyz will not match abcdxyz, because the error  occurs  at	the  `x',
       where approximation is turned off.

       Entire  path  segments  may  be	matched  approximately,  so  that  `(#a1)/foo/d/is/avail-
       able/at/the/bar' allows one error in any path segment.  This is much less  efficient  than
       without the (#a1), however, since every directory in the path must be scanned for a possi-
       ble approximate match.  It is best to place the (#a1) after any path  segments  which  are
       known to be correct.

   Recursive Globbing
       A  pathname  component  of  the	form  `(foo/)#' matches a path consisting of zero or more
       directories matching the pattern foo.

       As a shorthand, `**/' is equivalent to `(*/)#'; note that this therefore matches files  in
       the current directory as well as subdirectories.  Thus:

	      ls (*/)#bar


	      ls **/bar

       does  a	recursive  directory search for files named `bar' (potentially including the file
       `bar' in the current directory).  This form does not follow symbolic links;  the  alterna-
       tive  form `***/' does, but is otherwise identical.  Neither of these can be combined with
       other forms of globbing within the same path segment; in  that  case,  the  `*'	operators
       revert to their usual effect.

   Glob Qualifiers
       Patterns  used  for filename generation may end in a list of qualifiers enclosed in paren-
       theses.	The qualifiers specify which filenames that otherwise  match  the  given  pattern
       will be inserted in the argument list.

       If  the option BARE_GLOB_QUAL is set, then a trailing set of parentheses containing no `|'
       or `(' characters (or `~' if it is special) is taken as a set of glob qualifiers.  A  glob
       subexpression  that would normally be taken as glob qualifiers, for example `(^x)', can be
       forced to be treated as part of the glob pattern by doubling the parentheses, in this case
       producing `((^x))'.

       A qualifier may be any one of the following:

       /      directories

       .      plain files

       @      symbolic links

       =      sockets

       p      named pipes (FIFOs)

       *      executable plain files (0100)

       %      device files (character or block special)

       %b     block special files

       %c     character special files

       r      owner-readable files (0400)

       w      owner-writable files (0200)

       x      owner-executable files (0100)

       A      group-readable files (0040)

       I      group-writable files (0020)

       E      group-executable files (0010)

       R      world-readable files (0004)

       W      world-writable files (0002)

       X      world-executable files (0001)

       s      setuid files (04000)

       S      setgid files (02000)

       t      files with the sticky bit (01000)

       fspec  files  with access rights matching spec. This spec may be a octal number optionally
	      preceded by a `=', a `+', or a `-'. If none  of  these  characters  is  given,  the
	      behavior	is  the  same  as for `='. The octal number describes the mode bits to be
	      expected, if combined with a  `=',  the  value  given  must  match  the  file-modes
	      exactly,	with  a  `+',  at  least  the bits in the given number must be set in the
	      file-modes, and with a `-', the bits in the number must not be set.  Giving  a  `?'
	      instead of a octal digit anywhere in the number ensures that the corresponding bits
	      in the file-modes are not checked, this is only useful in combination with `='.

	      If the qualifier `f' is followed by any other character anything	up  to	the  next
	      matching	character  (`[',  `{',	and `<' match `]', `}', and `>' respectively, any
	      other character matches itself) is taken as a list  of  comma-separated  sub-specs.
	      Each  sub-spec may be either an octal number as described above or a list of any of
	      the characters `u', `g', `o', and `a', followed by a `=', a `+', or a `-', followed
	      by  a list of any of the characters `r', `w', `x', `s', and `t', or an octal digit.
	      The first list of characters specify which access rights are to be  checked.  If	a
	      `u' is given, those for the owner of the file are used, if a `g' is given, those of
	      the group are checked, a `o' means to test those of other users, and the	`a'  says
	      to  test all three groups. The `=', `+', and `-' again says how the modes are to be
	      checked and have the same meaning as described for the first form above. The second
	      list  of	characters  finally  says which access rights are to be expected: `r' for
	      read access, `w' for write access, `x' for the right to execute  the  file  (or  to
	      search  a  directory),  `s'  for the setuid and setgid bits, and `t' for the sticky

	      Thus, `*(f70?)' gives the files for which the owner has read,  write,  and  execute
	      permission,  and	for  which other group members have no rights, independent of the
	      permissions for other users. The pattern `*(f-100)' gives all files for  which  the
	      owner  does  not have execute permission, and `*(f:gu+w,o-rx:)' gives the files for
	      which the owner and the other members of the group have at least write  permission,
	      and for which other users don't have read or execute permission.

	      The  string  will  be executed as shell code.  The filename will be included in the
	      list if and only if the code returns a zero status (usually the status of the  last
	      command).   The  first character after the `e' will be used as a separator and any-
	      thing up to the next matching separator will be taken  as the string; `[', `{', and
	      `<'  match  `]',	`}',  and  `>',  respectively,	while any other character matches
	      itself. Note that expansions must be quoted in the  string  to  prevent  them  from
	      being expanded before globbing is done.

	      During  the execution of string the filename currently being tested is available in
	      the parameter REPLY; the parameter may be altered to a string to be  inserted  into
	      the list instead of the original filename.  In addition, the parameter reply may be
	      set to an array or a string, which overrides the value of  REPLY.   If  set  to  an
	      array, the latter is inserted into the command line word by word.

	      For example, suppose a directory contains a single file `lonely'.  Then the expres-
	      sion `*(e:'reply=(${REPLY}{1,2})':)' will cause the words `lonely1 lonely2'  to  be
	      inserted into the command line.  Note the quotation marks.

       ddev   files on the device dev

	      files having a link count less than ct (-), greater than ct (+), or equal to ct

       U      files owned by the effective user ID

       G      files owned by the effective group ID

       uid    files  owned  by user ID id if it is a number, if not, than the character after the
	      `u' will be used as a separator and the string between it  and  the  next  matching
	      separator  (`[', `{', and `<' match `]', `}', and `>' respectively, any other char-
	      acter matches itself) will be taken as a user name, and the user ID  of  this  user
	      will be taken (e.g. `u:foo:' or `u[foo]' for user `foo')

       gid    like uid but with group IDs or names

	      files  accessed  exactly	n  days  ago.	Files accessed within the last n days are
	      selected using a negative value for n (-n).  Files accessed more than  n	days  ago
	      are  selected  by a positive n value (+n).  Optional unit specifiers `M', `w', `h',
	      `m' or `s' (e.g. `ah5') cause the check to be performed with months (of  30  days),
	      weeks,  hours,  minutes  or  seconds  instead of days, respectively.  For instance,
	      `echo *(ah-5)' would echo files accessed within the last five hours.

	      like the file access qualifier, except that it uses the file modification time.

	      like the file access qualifier, except that it uses the file inode change time.

	      files less than n bytes (-), more than n bytes (+), or exactly n bytes  in  length.
	      If  this	flag  is  directly followed by a `k' (`K'), `m' (`M'), or `p' (`P') (e.g.
	      `Lk-50') the check is performed with kilobytes, megabytes, or blocks (of 512 bytes)

       ^      negates all qualifiers following it

       -      toggles  between making the qualifiers work on symbolic links (the default) and the
	      files they point to

       M      sets the MARK_DIRS option for the current pattern

       T      appends a trailing qualifier mark to the filenames,  analogous  to  the  LIST_TYPES
	      option, for the current pattern (overrides M)

       N      sets the NULL_GLOB option for the current pattern

       D      sets the GLOB_DOTS option for the current pattern

       n      sets the NUMERIC_GLOB_SORT option for the current pattern

       oc     specifies how the names of the files should be sorted. If c is n they are sorted by
	      name (the default); if it is L they are sorted depending on the  size  (length)  of
	      the  files;  if  l  they	are sorted by the number of links; if a, m, or c they are
	      sorted by the time of the last access, modification, or inode change  respectively;
	      if  d, files in subdirectories appear before those in the current directory at each
	      level of the search --- this is best combined  with  other  criteria,  for  example
	      `odon' to sort on names for files within the same directory.  Note that a, m, and c
	      compare the age against the current time, hence the first name in the list  is  the
	      youngest	file. Also note that the modifiers ^ and - are used, so `*(^-oL)' gives a
	      list of all files sorted by file size in descending order, following  any  symbolic

       Oc     like  `o',  but sorts in descending order; i.e. `*(^oc)' is the same as `*(Oc)' and
	      `*(^Oc)' is the same as `*(oc)'; `Od' puts files in the  current	directory  before
	      those in subdirectories at each level of the search.

	      specifies  which	of the matched filenames should be included in the returned list.
	      The syntax is the same as for array subscripts. beg and the  optional  end  may  be
	      mathematical expressions. As in parameter subscripting they may be negative to make
	      them count from the last match backward. E.g.: `*(-OL[1,3])' gives a  list  of  the
	      names of the three largest files.

       More  than one of these lists can be combined, separated by commas. The whole list matches
       if at least one of the sublists matches (they are `or'ed, the qualifiers in  the  sublists
       are  `and'ed).  Some qualifiers, however, affect all matches generated, independent of the
       sublist in which they are given.  These are the qualifiers `M', `T', `N', `D',  `n',  `o',
       `O' and the subscripts given in brackets (`[...]').

       If  a  `:'  appears in a qualifier list, the remainder of the expression in parenthesis is
       interpreted as a modifier (see the section `Modifiers'  in  the	section  `History  Expan-
       sion').	Note that each modifier must be introduced by a separate `:'.  Note also that the
       result after modification does not have to be an existing file.	The name of any  existing
       file  can be followed by a modifier of the form `(:..)' even if no actual filename genera-
       tion is performed.  Thus:

	      ls *(-/)

       lists all directories and symbolic links that point to directories, and

	      ls *(%W)

       lists all world-writable device files in the current directory, and

	      ls *(W,X)

       lists all files in the current directory that are world-writable or world-executable, and

	      echo /tmp/foo*(u0^@:t)

       outputs the basename of all root-owned files beginning with  the  string  `foo'	in  /tmp,
       ignoring symlinks, and

	      ls *.*~(lex|parse).[ch](^D^l1)

       lists all files having a link count of one whose names contain a dot (but not those start-
       ing with a dot, since GLOB_DOTS is explicitly  switched	off)  except  for  lex.c,  lex.h,
       parse.c and parse.h.

zsh 4.0.6				 August 14, 2002			       ZSHEXPN(1)
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