'\" '\" Copyright (c) 1993 The Regents of the University of California. '\" Copyright (c) 1994-1996 Sun Microsystems, Inc. '\" Copyright (c) 2000 Scriptics Corporation. '\" '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. '\" '\" RCS: @(#) regsub.n,v 1.5 2003/01/21 19:40:00 hunt Exp '\" .so man.macros .TH regsub n 8.3 Tcl "Tcl Built-In Commands" .BS '\" Note: do not modify the .SH NAME line immediately below! .SH NAME regsub \- Perform substitutions based on regular expression pattern matching .SH SYNOPSIS .VS 8.4 \fBregsub \fR?\fIswitches\fR? \fIexp string subSpec \fR?\fIvarName\fR? .VE 8.4 .BE .SH DESCRIPTION .PP This command matches the regular expression \fIexp\fR against \fIstring\fR, .VS 8.4 and either copies \fIstring\fR to the variable whose name is given by \fIvarName\fR or returns \fIstring\fR if \fIvarName\fR is not present. .VE 8.4 (Regular expression matching is described in the \fBre_syntax\fR reference page.) If there is a match, then while copying \fIstring\fR to \fIvarName\fR .VS 8.4 (or to the result of this command if \fIvarName\fR is not present) .VE 8.4 the portion of \fIstring\fR that matched \fIexp\fR is replaced with \fIsubSpec\fR. If \fIsubSpec\fR contains a ``&'' or ``\e0'', then it is replaced in the substitution with the portion of \fIstring\fR that matched \fIexp\fR. If \fIsubSpec\fR contains a ``\e\fIn\fR'', where \fIn\fR is a digit between 1 and 9, then it is replaced in the substitution with the portion of \fIstring\fR that matched the \fIn\fR-th parenthesized subexpression of \fIexp\fR. Additional backslashes may be used in \fIsubSpec\fR to prevent special interpretation of ``&'' or ``\e0'' or ``\e\fIn\fR'' or backslash. The use of backslashes in \fIsubSpec\fR tends to interact badly with the Tcl parser's use of backslashes, so it's generally safest to enclose \fIsubSpec\fR in braces if it includes backslashes. .LP If the initial arguments to \fBregexp\fR start with \fB\-\fR then they are treated as switches. The following switches are currently supported: .TP 10 \fB\-all\fR All ranges in \fIstring\fR that match \fIexp\fR are found and substitution is performed for each of these ranges. Without this switch only the first matching range is found and substituted. If \fB\-all\fR is specified, then ``&'' and ``\e\fIn\fR'' sequences are handled for each substitution using the information from the corresponding match. .TP 15 \fB\-expanded\fR Enables use of the expanded regular expression syntax where whitespace and comments are ignored. This is the same as specifying the \fB(?x)\fR embedded option (see the \fBre_syntax\fR manual page). .TP 15 \fB\-line\fR 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 `$' matches an empty string before any newline in addition to its normal function. This flag is equivalent to specifying both \fB\-linestop\fR and \fB\-lineanchor\fR, or the \fB(?n)\fR embedded option (see the \fBre_syntax\fR manual page). .TP 15 \fB\-linestop\fR Changes the behavior of `[^' bracket expressions and `.' so that they stop at newlines. This is the same as specifying the \fB(?p)\fR embedded option (see the \fBre_syntax\fR manual page). .TP 15 \fB\-lineanchor\fR Changes the behavior of `^' and `$' (the ``anchors'') so they match the beginning and end of a line respectively. This is the same as specifying the \fB(?w)\fR embedded option (see the \fBre_syntax\fR manual page). .TP 10 \fB\-nocase\fR Upper-case characters in \fIstring\fR will be converted to lower-case before matching against \fIexp\fR; however, substitutions specified by \fIsubSpec\fR use the original unconverted form of \fIstring\fR. .TP 10 \fB\-start\fR \fIindex\fR 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 \fIindex\fR. \fIindex\fR will be constrained to the bounds of the input string. .TP 10 \fB\-\|\-\fR Marks the end of switches. The argument following this one will be treated as \fIexp\fR even if it starts with a \fB\-\fR. .PP .VS 8.4 If \fIvarName\fR is supplied, the command returns a count of the number of matching ranges that were found and replaced, otherwise the string after replacement is returned. .VE 8.4 See the manual entry for \fBregexp\fR for details on the interpretation of regular expressions. .SH "SEE ALSO" regexp(n), re_syntax(n) .SH KEYWORDS match, pattern, regular expression, substitute