regsub [ switches ] exp string subSpec varName
This command matches the regular expression exp against
string, and it copies string to the variable
whose name is given by varName. The command returns 1 if
there is a match and 0 if there isn't. If there is a match, then
while copying string to varName the portion of
string that matches 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:
& and
\n sequences are handled for each substitution
using the information from the corresponding match.
See the manual entry for regexp for details on the interpretation of regular expressions.