Shell Programming and Scripting

I have a master list of servers. I also have a list of servers I'm not supposed to touch. I'm trying to filter out the list servers that I'm not supposed to touch from the master list of servers, so I will have a "master list of servers I can touch". When I try to filter these I'm not getting the desired result:

Code:

for i in $(cat dont_touch_list);do grep -iv $i master_list; done | uniq > master_touch_list

What this is doing, it appears, is echoing the master_list into the master_touch_list for each interation of the dont_touch_list. What am I doing wrong?

The problem is with the grep "-v" option, it prints all lines that don't match a pattern, in your case the value of ${i}.

Try:

Code:

for i in $(cat dont_touch_list);do grep -iv $i master_list; done | sort | uniq > master_touch_list

Try this...

Code:

grep -vf dont_touch_list master_list > master_touch_list

--ahamed

You can probably use the join utility to do what you want to do.

For example, if do-not-touch file contains:

Code:

a
b
c

and master-list file contains:

Code:

a
b
c
d
e
f

Assuming the files are sorted:

Code:

$ join -v 2 do-not-touch master-list
d
e
f

This did not produce the desired result. For some reason the master_touch_list still had items in it from the dont_touch_list. But thank you for the suggestion!

Without going through and individually checking each and every item in the master_touch_list this appears to have worked. Running a for loop grepping each item from the dont_touch_list in the master_touch_list produced no results so I think I'm good. Appreciate your help and I'll keep murphy's suggestion in mind as well.