Consider I have the following stream of data:

```
BODY1
attrib1:  someval11
attrib2:  someval12
attrib3:  someval13

BODY2
attrib1:  someval21
attrib2:  someval22
attrib3:  someval23

BODY3
attrib1:  someval31
attrib2:  someval32
attrib3:  someval33

```

I want to extract **only attrib1 and attrib3** for each BODY, i.e.

```
attrib1:  someval11
attrib3:  someval13
attrib1:  someval21
attrib3:  someval23
attrib1:  someval31
attrib3:  someval33

```

I tried

`grep 'attrib1\|attrib3'`, according to [this site](http://www.cyberciti.biz/faq/searching-multiple-words-string-using-grep/) but that returned nothing. `grep attrib1` and `grep attrib2` do return data but just for the single pattern specified.