Comments for HandsomePlanet http://www.handsomeplanet.com technology and other perplexities Fri, 08 Oct 2010 16:19:14 +0000 hourly 1 http://wordpress.org/?v=3.3.1 Comment on Cisco IOS CLI regular expressions, Part II — ‘AND’ by admin http://www.handsomeplanet.com/archives/11/comment-page-1#comment-9 admin Fri, 08 Oct 2010 16:19:14 +0000 http://www.handsomeplanet.com/?p=11#comment-9 I understand that it is possible to create more precise matches using the method you have described well here. In practice, it makes more sense to match only what needs to be matched with the least possible typing. While you are correct that there are multiple matches with a partial representation of the regex for an IP, on a live network it is usually sufficient to get close. If you are doing 'show run' and are matching an IP, you are matching the output of a static config, and presumably searching for known data. Even for dynamic data with many possible matches, it often makes more sense to do a quick and inexact search and then refine your regular expression to get the match you need (based on the output). This also cuts down on typos. Enclosing the expression in parens will also take care of space matching, if one is disinclined to use the underscores (as I am). I understand that it is possible to create more precise matches using the method you have described well here. In practice, it makes more sense to match only what needs to be matched with the least possible typing. While you are correct that there are multiple matches with a partial representation of the regex for an IP, on a live network it is usually sufficient to get close. If you are doing ‘show run’ and are matching an IP, you are matching the output of a static config, and presumably searching for known data. Even for dynamic data with many possible matches, it often makes more sense to do a quick and inexact search and then refine your regular expression to get the match you need (based on the output). This also cuts down on typos. Enclosing the expression in parens will also take care of space matching, if one is disinclined to use the underscores (as I am).

]]> Comment on Cisco IOS CLI regular expressions, Part II — ‘AND’ by ciscozine http://www.handsomeplanet.com/archives/11/comment-page-1#comment-8 ciscozine Fri, 08 Oct 2010 14:21:23 +0000 http://www.handsomeplanet.com/?p=11#comment-8 To check exacly an IP address use the backslash (\) before the dot (.) to remove the special meaning of the dot (.) character and the underscore (_) to check the space before/after the IP address. For example, to find the ip address 10.0.0.1 in the running configuration, use the command show run | i _10\.0\.0\.1_ and not the command (it can match 10.0.0.1, 110.0.0.1, 10.1.1.11, …) show run | i 10.0.0.1 More info on http://www.ciscozine.com/2010/10/06/using-regular-expressions-with-the-show-command/ To check exacly an IP address use the backslash (\) before the dot (.) to remove the special meaning of the dot (.) character and the underscore (_) to check the space before/after the IP address. For example, to find the ip address 10.0.0.1 in the running configuration, use the command

show run | i _10\.0\.0\.1_

and not the command (it can match 10.0.0.1, 110.0.0.1, 10.1.1.11, …)

show run | i 10.0.0.1

More info on http://www.ciscozine.com/2010/10/06/using-regular-expressions-with-the-show-command/

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