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RedHat 9 (Linux i386) - man page for regsub (redhat section n)

regsub(n)			      Tcl Built-In Commands				regsub(n)

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NAME
       regsub - Perform substitutions based on regular expression pattern matching

SYNOPSIS
       regsub ?switches? exp string subSpec varName
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DESCRIPTION
       This  command  matches  the regular expression exp against string, and it copies string to
       the variable whose name is given by varName.  (Regular expression matching is described in
       the  re_syntax reference page.)	If there is a match, then while copying string to varName
       the portion of string that matched exp is replaced with subSpec.  If  subSpec  contains	a
       ``&''  or  ``\0'', then it is replaced in the substitution with the portion of string that
       matched exp.  If subSpec contains a ``\n'', where n is a digit between 1 and 9, then it is
       replaced  in  the  substitution with the portion of string that matched the n-th parenthe-
       sized subexpression of exp.  Additional backslashes may be used in subSpec to prevent spe-
       cial  interpretation of ``&'' or ``\0'' or ``\n'' or backslash.	The use of backslashes in
       subSpec tends to interact badly with the Tcl parser's use of backslashes, so  it's  gener-
       ally safest to enclose subSpec in braces if it includes backslashes.

       If  the	initial  arguments to regexp start with - then they are treated as switches.  The
       following switches are currently supported:

       -all	 All ranges in string that match exp are found and substitution is performed  for
		 each  of  these  ranges.   Without  this switch only the first matching range is
		 found and substituted.  If -all is specified, then ``&''  and	``\n''	sequences
		 are  handled  for each substitution using the information from the corresponding
		 match.

       -expanded      Enables use of the expanded regular expression syntax where whitespace  and
		      comments	are  ignored.	This  is the same as specifying the (?x) embedded
		      option (see METASYNTAX, below).

       -line	      Enables newline-sensitive matching.  By default, newline	is  a  completely
		      ordinary	character  with no special meaning.  With this flag, `[^' bracket
		      expressions and `.' never match newline, `^' matches an empty string  after
		      any  newline  in	addition to its normal function, and `$' matches an empty
		      string before any newline in addition to its normal function.  This flag is
		      equivalent to specifying both -linestop and -lineanchor, or the (?n) embed-
		      ded option (see METASYNTAX, below).

       -linestop      Changes the behavior of `[^' bracket expressions and `.' so that they  stop
		      at  newlines.  This is the same as specifying the (?p) embedded option (see
		      METASYNTAX, below).

       -lineanchor    Changes the behavior of `^' and `$' (the ``anchors'')  so  they  match  the
		      beginning  and  end of a line respectively.  This is the same as specifying
		      the (?w) embedded option (see METASYNTAX, below).

       -nocase	 Upper-case characters in string will be converted to lower-case before  matching
		 against  exp;	 however,  substitutions  specified  by  subSpec use the original
		 unconverted form of string.							  |

       -start index										  |
		 Specifies a character index offset into the string to start matching the regular |
		 expression  at.  When using this switch, `^' will not match the beginning of the |
		 line, and \A will still match the start of the string at index.  index  will  be |
		 constrained to the bounds of the input string.

       --	 Marks	the  end of switches.  The argument following this one will be treated as
		 exp even if it starts with a -.

       The command returns a count of the number of matching ranges that were found and replaced.
       See the manual entry for regexp for details on the interpretation of regular expressions.

SEE ALSO
       regexp(n), re_syntax(n)

KEYWORDS
       match, pattern, regular expression, substitute

Tcl					       8.3					regsub(n)


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