{"id":6138,"date":"2022-12-20T18:57:57","date_gmt":"2022-12-20T21:57:57","guid":{"rendered":"http:\/\/lode.uno\/linux-man\/index.php\/2022\/12\/20\/regsub-mann\/"},"modified":"2022-12-20T18:57:57","modified_gmt":"2022-12-20T21:57:57","slug":"regsub-mann","status":"publish","type":"post","link":"https:\/\/lode.uno\/linux-man\/2022\/12\/20\/regsub-mann\/","title":{"rendered":"regsub (mann)"},"content":{"rendered":"

regsub<\/h1>\n

NAME<\/a>
SYNOPSIS<\/a>
DESCRIPTION<\/a>
EXAMPLES<\/a>
SEE ALSO<\/a>
KEYWORDS<\/a> <\/p>\n

\n

______________________________________________________________________________<\/p>\n

NAME <\/a> <\/h2>\n

regsub \u2212 Perform substitutions based on regular expression pattern matching<\/p>\n

SYNOPSIS <\/a> <\/h2>\n

regsub<\/b> ?switches<\/i>? exp string subSpec<\/i> ?varName<\/i>? ______________________________________________________________________________<\/p>\n

DESCRIPTION <\/a> <\/h2>\n

This command matches the regular expression exp<\/i> against string<\/i>, and either copies string<\/i> to the variable whose name is given by varName<\/i> or returns string<\/i> if varName<\/i> is not present. (Regular expression matching is described in the re_syntax<\/b> reference page.) If there is a match, then while copying string<\/i> to varName<\/i> (or to the result of this command if varName<\/i> is not present) the portion of string<\/i> that matched exp<\/i> is replaced with subSpec<\/i>. If subSpec<\/i> contains a \u201c&\u201d or \u201c\u0000\u201d, then it is replaced in the substitution with the portion of string<\/i> that matched exp<\/i>. If subSpec<\/i> contains a \u201cn<\/i>\u201d, where n<\/i> is a digit between 1 and 9, then it is replaced in the substitution with the portion of string<\/i> that matched the n<\/i>\u2019th parenthesized subexpression of exp<\/i>. Additional backslashes may be used in subSpec<\/i> to prevent special interpretation of \u201c&\u201d, \u201c\u0000\u201d, \u201cn<\/i>\u201d and backslashes. The use of backslashes in subSpec<\/i> tends to interact badly with the Tcl parser\u2019s use of backslashes, so it is generally safest to enclose subSpec<\/i> in braces if it includes backslashes.<\/p>\n

If the initial arguments to regsub<\/b> start with \u2212<\/b> then they are treated as switches. The following switches are currently supported:<\/p>\n\n\n
<\/td>\n\n

\u2212all<\/b><\/p>\n<\/td>\n

<\/td>\n\n

All ranges in string<\/i> that match exp<\/i> are found and substitution is performed for each of these ranges. Without this switch only the first matching range is found and substituted. If \u2212all<\/b> is specified, then \u201c&\u201d and \u201cn<\/i>\u201d sequences are handled for each substitution using the information from the corresponding match.<\/p>\n<\/td>\n<\/tr>\n<\/table>\n

\u2212expanded<\/b><\/p>\n

Enables use of the expanded regular expression syntax where whitespace and comments are ignored. This is the same as specifying the (?x)<\/b> embedded option (see the re_syntax<\/b> manual page).<\/p>\n\n\n
<\/td>\n\n

\u2212line<\/b><\/p>\n<\/td>\n

<\/td>\n\n

Enables newline-sensitive matching. By default, newline is a completely ordinary character with no special meaning. With this flag, \u201c[^\u201d bracket expressions and \u201c.\u201d never match newline, \u201c^\u201d matches an empty string after any newline in addition to its normal function, and \u201c$\u201d matches an empty string before any newline in addition to its normal function. This flag is equivalent to specifying both \u2212linestop<\/b> and \u2212lineanchor<\/b>, or the (?n)<\/b> embedded option (see the re_syntax<\/b> manual page).<\/p>\n<\/td>\n<\/tr>\n<\/table>\n

\u2212linestop<\/b><\/p>\n

Changes the behavior of \u201c[^\u201d bracket expressions and \u201c.\u201d so that they stop at newlines. This is the same as specifying the (?p)<\/b> embedded option (see the re_syntax<\/b> manual page).<\/p>\n

\u2212lineanchor<\/b><\/p>\n

Changes the behavior of \u201c^\u201d and \u201c$\u201d (the \u201canchors\u201d) so they match the beginning and end of a line respectively. This is the same as specifying the (?w)<\/b> embedded option (see the re_syntax<\/b> manual page).<\/p>\n

\u2212nocase<\/b><\/p>\n

Upper-case characters in string<\/i> will be converted to lower-case before matching against exp<\/i>; however, substitutions specified by subSpec<\/i> use the original unconverted form of string<\/i>.<\/p>\n

\u2212start<\/b> index<\/i><\/p>\n

Specifies a character index offset into the string to start matching the regular expression at. The index<\/i> value is interpreted in the same manner as the index<\/i> argument to string index<\/b>. When using this switch, \u201c^\u201d will not match the beginning of the line, and A will still match the start of the string at index<\/i>. index<\/i> will be constrained to the bounds of the input string.<\/p>\n\n\n
<\/td>\n\n

\u2212\u2212<\/b><\/p>\n<\/td>\n

<\/td>\n\n

Marks the end of switches. The argument following this one will be treated as exp<\/i> even if it starts with a \u2212<\/b>.<\/p>\n<\/td>\n<\/tr>\n<\/table>\n

If varName<\/i> 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. See the manual entry for regexp<\/b> for details on the interpretation of regular expressions.<\/p>\n

EXAMPLES <\/a> <\/h2>\n

Replace (in the string in variable string<\/i>) every instance of foo<\/b> which is a word by itself with bar<\/b>:<\/p>\n

regsub<\/b> -all {mfooM} $string bar string<\/p>\n

or (using the \u201cbasic regular expression\u201d syntax):<\/p>\n

regsub<\/b> -all {(?b)} $string bar string<\/p>\n

Insert double-quotes around the first instance of the word interesting<\/b>, however it is capitalized.<\/p>\n

regsub<\/b> -nocase {yinterestingy} $string {“&”} string<\/p>\n

Convert all non-ASCII and Tcl-significant characters into u escape sequences by using regsub<\/b> and subst<\/b> in combination:<\/p>\n

# This RE is just a character class for almost everything “bad”
set RE {[][{};#\\$ rtu0080-uffff]}<\/p>\n

# We will substitute with a fragment of Tcl script in brackets
set substitution {[format \\\\u%04x [scan “\\&” %c]]}<\/p>\n

# Now we apply the substitution to get a subst-string that
# will perform the computational parts of the conversion. Note
# that newline is handled specially through string map<\/b> since
# backslash-newline is a special sequence.
set quoted [subst [string map {n {\\u000a}}
[regsub<\/b> -all $RE $string $substitution]]]<\/p>\n

SEE ALSO <\/a> <\/h2>\n

regexp(n), re_syntax(n), subst(n), string(n)<\/p>\n

KEYWORDS <\/a> <\/h2>\n

match, pattern, quoting, regular expression, substitution<\/p>\n

\n","protected":false},"excerpt":{"rendered":"

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