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Find string length using regexp
We can find the length of the string using regexp command, '.' is to map any charecter in given pattern,
set stiring "network"
set length [regexp -all . $string]
TCL program to Extract all IP address form the output given below.
OPSF:OSPF_NBRUP OSPF neighbor 216.138.181.15 (realm ospf-v2 e1-0/0/0:37.0 area 0.0.0.0) state changed from Full to Down due to KillNbr 13.12.1.0
set string "OSPF_NBRUP OSPF neighbor 216.138.181.15 (realm ospf-v2 e1-0/0/0:37.0 area 0.0.0.0) state changed from Full to Down due to KillNbr 13.12.1.0"
set a [regexp -all -inline {(?:\d+\.){3}\d+} $string]
puts $a
TCL program to List all words (consisting of all sequences of non-whitespace characters) in a string
regexp -all -inline {\S+} $string
TCL program to Reverse string
proc strrev str {
set res {}
set i [string length $str]
while {$i > 0} {
append res [string index $str [incr i -1]]}
set res
}
#matching any ip address
set str 192.168.3.110
regexp {(^[0-9]{1,3})\.([0-9]{1,3})\.([0-9]{1,3})\.([0-9]{1,3})$} $str all first second third fourth
puts "$all \n $first \n $second \n $third \n $fourth \n"
if {$first <= 255 && $second <= 255 && $third <= 255 && $fourth <= 255} {
puts "valid ip address"
} else {
puts "invlaid ip address"
}
#to match any email address
set a "Raj_btech23@rediffmail.com"
if {[regexp -- {^[A-Za-z0-9._-]+@[[A-Za-z0-9.-]+$} $a b]} {
puts $b
} else {
puts fail
}
#puts $a
If the initial arguments to [regexp]] start with - then they are treated as switches. The following switches are currently supported:
-about
Instead of attempting to match the regular expression, returns a list containing information about the regular expression. The first element of the list is a subexpression count. The second element is a list of property names that describe various attributes of the regular expression. This switch is primarily intended for debugging purposes (see REGEXP DESCRIPTIVE FLAGS below).
-expanded
Enables use of the expanded regular expression syntax where whitespace and comments are ignored. This is the same as specifying the (?x) embedded option (see METASYNTAX, below).
-indices
Changes what is stored in the subMatchVars. Instead of storing the matching characters from string, each variable will contain a list of two integers giving the indices in string of the first and last characters in the matching range of characters.
-line
Enables newline-sensitive matching. By default, newline is a completely ordinary character with no special meaning. With this flag, ‘[^’ bracket expressions and ‘.’ never match newline, ‘^’ matches an empty string after any newline in addition to its normal function, and ‘$’ matches an empty string before any newline in addition to its normal function. This flag is equivalent to specifying both -linestop and -lineanchor, or the (?n) embedded option (see METASYNTAX, below).
-linestop
Changes the behavior of ‘[^’ bracket expressions and ‘.’ so that they stop at newlines. This is the same as specifying the (?p) embedded option (see METASYNTAX, below).
-lineanchor
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 (?w) embedded option (see METASYNTAX, below).
-nocase
Causes upper-case characters in string to be treated as lower case during the matching process.
-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 -.