regsub(3Tcl)

NAME
     regsub - Perform substitutions based on regular expression pattern
     matching

SYNOPSIS
     regsub ?switches? exp string subSpec varName


DESCRIPTION
     This command matches the regular expression exp against string, and it   |
     copies string to the variable whose name is given by varName.  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 parenthesized subexpression of
     exp.  Additional backslashes may be used in subSpec to prevent special
     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 generally 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.

     -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.

     --        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.


KEYWORDS
     match, pattern, regular expression, substitute