Help with looping a file and grepping a string


 
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Operating Systems AIX Help with looping a file and grepping a string
# 1  
Old 04-07-2011
Java Help with looping a file and grepping a string

I have 2 files: fileA and fileB.

content of fileA
---------------
admin.teacher is in new york;
admin.mason is in new york;
admin.driver is in new york city;
user.trucker is in hartford;
admin.developer is in new york state;

content of fileB
----------------
admin.teacher is in chigago;
user.teacher is in new york;
admin.mason is in new york;
admin.developer is in new york state
admin.plumber is in new york;
admin.driver is in new york city;
user.trucker is in hartford;
admin.nurse is in new york state;
admin.teacher is in new york
user.painter is in new york;


This is what I am trying to achieve:
I would like to loop through fileB and if any member in fileA
is found in fileB then that line in fileB will be commented with (--)
I am looking for a neat script to do this for me. thx.

This means that the resulting file to look like:

FileC
----------
admin.teacher is in chigago;
user.teacher is in new york;
--admin.mason is in new york;
--admin.developer is in new york state
admin.plumber is in new york;
--admin.driver is in new york city;
--user.trucker is in hartford;
admin.nurse is in new york state;
--admin.teacher is in new york
user.painter is in new york;
# 2  
Old 04-07-2011
You will learn faster if you do your own homework.
# 3  
Old 04-07-2011
crap. you if dont have anything to offer dont say nothin. Do i have to tell you how much effort i have put in before trying to seek help from the forum?
# 4  
Old 04-07-2011
Maybe try smthg like
Code:
awk 'NR==FNR{A[$0]=1}NR!=FNR{print (A[$0]?"--"$0:$0)}' fileA fileB >fileC

... by the way , your example lack the trailing semicolon in fileB for the 2 lines :
Code:
admin.developer is in new york state
admin.teacher is in new york

Use nawk instead of awk if on SunOS / Solaris plateform

Code:
# cat f1
admin.teacher is in new york;
admin.mason is in new york;
admin.driver is in new york city;
user.trucker is in hartford;
admin.developer is in new york state;

Code:
# cat f2
admin.teacher is in chigago;
user.teacher is in new york;
admin.mason is in new york;
admin.developer is in new york state;
admin.plumber is in new york;
admin.driver is in new york city;
user.trucker is in hartford;
admin.nurse is in new york state;
admin.teacher is in new york;
user.painter is in new york;

Code:
# nawk 'NR==FNR{A[$0]=1}NR!=FNR{print (A[$0]?"--"$0:$0)}' f1 f2
admin.teacher is in chigago;
user.teacher is in new york;
--admin.mason is in new york;
--admin.developer is in new york state;
admin.plumber is in new york;
--admin.driver is in new york city;
--user.trucker is in hartford;
admin.nurse is in new york state;
--admin.teacher is in new york;
user.painter is in new york;


Last edited by ctsgnb; 04-07-2011 at 03:08 PM..
This User Gave Thanks to ctsgnb For This Post:
# 5  
Old 04-07-2011
awesome!
You made it look so easy. I tried doing looping and greping with some intemediate files. Even though I finally got it to work, the approach was not pretty and I did not like it.
Your solution is just excellent. I love one-liners and this solution is just cool. Works like a charm . Thanks

---------- Post updated at 01:13 PM ---------- Previous update was at 01:10 PM ----------

Deliverer,
could you give some short explanation how your code works? in other words decipher it? lol

'NR==FNR{A[$0]=1}NR!=FNR{print (A[$0]?"
# 6  
Old 04-07-2011
Before explaining further, please consider the following statement, observe what happend in each column and with a bit of deduction you will get it
This should help you to understand :

Code:
# nawk '{print NR,FNR,FILENAME,$0}' f1 f2
1 1 f1 admin.teacher is in new york;
2 2 f1 admin.mason is in new york;
3 3 f1 admin.driver is in new york city;
4 4 f1 user.trucker is in hartford;
5 5 f1 admin.developer is in new york state;
6 1 f2 admin.teacher is in chigago;
7 2 f2 user.teacher is in new york;
8 3 f2 admin.mason is in new york;
9 4 f2 admin.developer is in new york state;
10 5 f2 admin.plumber is in new york;
11 6 f2 admin.driver is in new york city;
12 7 f2 user.trucker is in hartford;
13 8 f2 admin.nurse is in new york state;
14 9 f2 admin.teacher is in new york;
15 10 f2 user.painter is in new york;

---------- Post updated at 08:35 PM ---------- Previous update was at 08:18 PM ----------

if NR==FNR, we are scanning the first file we build an associative array indexed by the content of the line
if NR!=FNR, we are scanning the other file (note that when the scan of the second file start, the first file has already been entirely scanned so if an element of the previously built array is found based on the content of $0, then we add it "--"$0 otherwise we just leave it as is :$0
# 7  
Old 04-07-2011
ctsgnb, hey genius, are you an instructor at MIT? thanks a lot
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