regsub - Perform substitutions based on regular expression pattern matching
regsub ?switches? exp string subSpec varName
This command matches the regular expression exp against
and it copies string to the variable whose name is
given by varName.
(Regular expression matching is described in the re_syntax
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
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
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
If the initial arguments to regexp start with - then
they are treated as switches. The following switches are
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.
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. If -indices
is specified, the indices will be indexed starting from the
absolute beginning of the input string.
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.
match, pattern, regular expression, substitute
Copyright © 1993 The Regents of the University of California.
Copyright © 1994-1996 Sun Microsystems, Inc.
Copyright © 1995-1997 Roger E. Critchlow Jr.