[rancid] excluding output from cisco routers and switches

[rdrake]

On 01/04/2016 03:16 PM, allonon wrote:
> I wanted to start a different topic as mine is not about flash or 
> bootflash.
>
> I have a similar issue with nexus output and want to prevent diff 
> emails but I want the data in the the saved config.  One of switches 
> will constantly adjust output watts by a few points.
>
>
>   !Env: -------  -------------------  ----------  ---------- 
>  ----------  --------------
> - !Env: 1        N9K-PAC-650W-B             67 W           649 W     Ok
> - !Env: 2        N9K-PAC-650W-B             71 W           649 W     Ok
> + !Env: 1        N9K-PAC-650W-B             68 W           649 W     Ok
> + !Env: 2        N9K-PAC-650W-B             70 W           649 W     Ok
>
>
> My scripting-fu is non-existent and am trying to learn this.
>
> I figure I have 3 options.
>     Just have Rancid ignore the line.  (not preferred as I want to see 
> the PS as OK or not)
>     Filter email output.
>     Filter the actual diff.  (can the diff actually handle advanced 
> parsing?  Everything I see shows how to ignore line based on simple match)
>
> I found this snippet from another thread on how to filter email output 
> but I'm getting lost on what it is doing after the first grep
> > DIFF=`cat $TMP.diff | grep -v "^===" | grep -v "^diff " | grep -v
> > "^Index: " | grep -v "^retrieving revision" | grep -v "^$"`
> > if [ -n "$DIFF" ]; then
> > ...email stuff here...
> > fi
>
> How do I best adjust this so that it greps for the ENV or N9K-PAC 
> line, and ignore (not send diff email) it if the Ok is there.
>
> Thanks
>
The multiple greps in that example are for different commands they want 
to match and exclude.  You can do something like this:

DIFF=`cat $TMP.diff | grep -Ev "[ +-] \!Env: [0-9]"`

You can test if your regex is working by making a fake diff and seeing 
if the grep matches :
[rdrake at test ~]$ cat test.in | grep -E "[ +-] \!Env: [0-9]"
- !Env: 1        N9K-PAC-650W-B             67 W 649 W     Ok
- !Env: 2        N9K-PAC-650W-B             71 W 649 W     Ok
+ !Env: 1        N9K-PAC-650W-B             68 W 649 W     Ok
+ !Env: 2        N9K-PAC-650W-B             70 W 649 W     Ok

[rdrake at test ~]$ cat test.in | grep -Ev "[ +-] \!Env: [0-9]"
   !Env: -------  -------------------  ----------  ---------- 
----------  --------------

(if you want to get rid of this line too you can use this)

[rdrake at test ~]$ cat test.in | grep -Ev "[ +-] \!Env: [0-9-]"
[rdrake at test ~]$

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