UNIX for Dummies Questions & Answers

Hi All

I'm still on my slow and painful self teach learning experience with SED.

My latest issue is getting my head around how best to do the following.

I have a file that's created using iwlist that I want to chop up into paragraphs then only keep the ones I see as potential threats.

I have managed to use sed to break the file up into identifiable paragraphs with a blank line as the paragraph break without too many problems, however what I want to do now is push each paragraph into an array then run various other sed scripts against each array to extract needed data.

I was trying to use something like....

Code:

echo "$IWLISTFILE" | sed -e '/StartPoint /,/\n\n/!d'

(or variations on the same) to cut everything except what's inside the StartPoint to the two newlines however it's not working as I was hoping and I can't see why. Instead it's not deleting anything or if I remove the EXCEPT in front of the delete it is deleting everything.

Could someone perhaps suggest what I'm missing/doing wrong in my understanding so that I can at least learn from the experience.

Thanks in advance.

sed is line based so you cannot look for \n characters that way:

Try this:

Code:

sed '/StartPoint /,/^$/!d' "$IWLISTFILE"

^$ means an empty line

Cripes what a tw*t I am, of course it's the obvious things you miss when you're still learning.

Thanks Scrutinizer....I'll go off and do 200 press ups now as a stupidity penance.

Hi Bashingaway, I think I can safely say we are all learning here. That is what makes Unix so interesting. Have fun..

S.