GNU.WIKI: The GNU/Linux Knowledge Base

  [HOME] [PHP Manual] [HowTo] [ABS] [MAN1] [MAN2] [MAN3] [MAN4] [MAN5] [MAN6] [MAN7] [MAN8] [MAN9]

  [0-9] [Aa] [Bb] [Cc] [Dd] [Ee] [Ff] [Gg] [Hh] [Ii] [Jj] [Kk] [Ll] [Mm] [Nn] [Oo] [Pp] [Qq] [Rr] [Ss] [Tt] [Uu] [Vv] [Ww] [Xx] [Yy] [Zz]


       glob - globbing pathnames


       Long  ago,  in UNIX V6, there was a program /etc/glob that would expand
       wildcard patterns.  Soon afterward this became a shell built-in.

       These days there is also a library routine glob(3)  that  will  perform
       this function for a user program.

       The rules are as follows (POSIX.2, 3.13).

   Wildcard matching
       A  string  is  a  wildcard pattern if it contains one of the characters
       '?', '*' or '['.  Globbing is the operation  that  expands  a  wildcard
       pattern  into  the list of pathnames matching the pattern.  Matching is
       defined by:

       A '?' (not between brackets) matches any single character.

       A '*' (not between brackets) matches any string,  including  the  empty

       Character classes

       An  expression  "[...]" where the first character after the leading '['
       is not an '!' matches a single character, namely any of the  characters
       enclosed  by  the brackets.  The string enclosed by the brackets cannot
       be empty; therefore ']' can be allowed between the  brackets,  provided
       that  it  is  the  first  character.   (Thus, "[][!]" matches the three
       characters '[', ']' and '!'.)


       There is one special convention: two characters separated by '-' denote
       a     range.      (Thus,     "[A-Fa-f0-9]"     is     equivalent     to
       "[ABCDEFabcdef0123456789]".)   One  may  include  '-'  in  its  literal
       meaning  by making it the first or last character between the brackets.
       (Thus, "[]-]" matches just the two characters ']' and '-', and  "[--0]"
       matches  the  three  characters  '-',  '.',  '0',  since  '/' cannot be


       An expression "[!...]" matches a single character, namely any character
       that  is  not  matched by the expression obtained by removing the first
       '!' from it.  (Thus, "[!]a-]" matches any single character except  ']',
       'a' and '-'.)

       One  can  remove  the  special meaning of '?', '*' and '[' by preceding
       them by a backslash, or, in case this is part of a shell command  line,
       enclosing  them in quotes.  Between brackets these characters stand for
       themselves.  Thus, "[[?*\]" matches the four characters '[',  '?',  '*'
       and '\'.

       Globbing is applied on each of the components of a pathname separately.
       A '/' in a pathname cannot be matched by a '?' or '*' wildcard, or by a
       range  like "[.-0]".  A range cannot contain an explicit '/' character;
       this would lead to a syntax error.

       If a filename starts  with  a  '.',  this  character  must  be  matched
       explicitly.  (Thus, rm * will not remove .profile, and tar c * will not
       archive all your files; tar c . is better.)

   Empty lists
       The nice and simple rule given above: "expand a wildcard  pattern  into
       the  list  of matching pathnames" was the original UNIX definition.  It
       allowed one to have patterns that expand into an empty list, as in

           xv -wait 0 *.gif *.jpg

       where perhaps no *.gif files are present (and this is  not  an  error).
       However,  POSIX requires that a wildcard pattern is left unchanged when
       it is syntactically incorrect, or the list  of  matching  pathnames  is
       empty.   With  bash  one  can  force  the classical behavior using this

           shopt -s nullglob

       (Similar problems occur elsewhere.  E.g., where old scripts have

           rm `find . -name "*~"`

       new scripts require

           rm -f nosuchfile `find . -name "*~"`

       to avoid error messages from rm called with an empty argument list.)


   Regular expressions
       Note that wildcard patterns are not regular expressions, although  they
       are  a  bit  similar.   First of all, they match filenames, rather than
       text, and secondly, the conventions are not the same: for example, in a
       regular  expression  '*'  means  zero  or  more copies of the preceding

       Now  that  regular  expressions  have  bracket  expressions  where  the
       negation  is  indicated  by  a  '^', POSIX has declared the effect of a
       wildcard pattern "[^...]" to be undefined.

   Character classes and internationalization
       Of course ranges were originally meant to  be  ASCII  ranges,  so  that
       "[ -%]"  stands  for  "[ !"#$%]"  and "[a-z]" stands for "any lowercase
       letter".  Some UNIX implementations generalized this so  that  a  range
       X-Y  stands for the set of characters with code between the codes for X
       and for Y.  However, this requires  the  user  to  know  the  character
       coding  in  use on the local system, and moreover, is not convenient if
       the collating sequence for the local alphabet differs from the ordering
       of the character codes.  Therefore, POSIX extended the bracket notation
       greatly, both for wildcard patterns and for  regular  expressions.   In
       the  above  we  saw  three  types  of items that can occur in a bracket
       expression: namely (i) the negation, (ii) explicit  single  characters,
       and  (iii)  ranges.   POSIX specifies ranges in an internationally more
       useful way and adds three more types:

       (iii) Ranges X-Y comprise all characters that  fall  between  X  and  Y
       (inclusive)  in  the  current  collating  sequence  as  defined  by the
       LC_COLLATE category in the current locale.

       (iv) Named character classes, like

       [:alnum:]  [:alpha:]  [:blank:]  [:cntrl:]
       [:digit:]  [:graph:]  [:lower:]  [:print:]
       [:punct:]  [:space:]  [:upper:]  [:xdigit:]

       so that one can say "[[:lower:]]" instead of "[a-z]", and  have  things
       work  in  Denmark,  too,  where there are three letters past 'z' in the
       alphabet.  These character classes are defined by the LC_CTYPE category
       in the current locale.

       (v) Collating symbols, like "[.ch.]" or "[.a-acute.]", where the string
       between "[." and ".]" is a collating element defined  for  the  current
       locale.  Note that this may be a multicharacter element.

       (vi)  Equivalence  class  expressions,  like  "[=a=]", where the string
       between "[=" and "=]" is any collating  element  from  its  equivalence
       class, as defined for the current locale.  For example, "[[=a=]]" might


       sh(1), fnmatch(3), glob(3), locale(7), regex(7)


       This  page  is  part of release 3.65 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at

  All copyrights belong to their respective owners. Other content (c) 2014-2018, GNU.WIKI. Please report site errors to
Page load time: 0.110 seconds. Last modified: November 04 2018 12:49:43.