pattern matching - tcl regex match ip address in a single line -

i trying write regexp check whether ip valid or not.facing issue when give 256 value still matching 2, , reg store value 1 since pattern matched.

set ip "256.256.255.1" set reg [regexp -all{^([1-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5]).([1-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5]).([1-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5]).([1-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])} $ip match ]  puts $reg 

the unescaped . match any character, not . symbol. capturing groups unnecessary since interested in 1 whole match. besides, no need use -all since want validate single string.

use

set text {256.256.255.1} set pattern {^(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])(?:\.(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])){3}$}  regexp $pattern $text match if {[info exists match]} {     puts $match } else {     puts "no match" } 

see online tcl demo.

pattern details:

• ^ - start of string
• (?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5]) - first octet matching numbers 0 255
• (?:\.(?:[0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])){3} - 3 occurrences of . (see \.) , octet subpattern
• $ - end of string.