How can i delete the contents of one file based on another file

rdhanek · #1 (**permalink**) 08-27-2009

Hi all,

I have two log files A and B. Where files A have 10 lines and file b has 5 lines.

Out of them 3 lines are common to both of them. I want to compare both the files and want to delete the common data from file A(file B should remain as it is)

example :

Code:

file A :
 
1
2
3
4
5
6
7
8
9
11
 
file B :
A
2
25
1
7

AND THE OUTPUT SHOULD BE

Code:

file A :
 
3
4
5
6
8
9
11
 
file B :
A
2
25
1
7

panyam · #2 (**permalink**) 08-27-2009

Something like this :

Code:

awk 'NR==FNR { a[$0]=$0 ;next } { if($0 in a) {a[$0]="";}} END { for ( i in a) print a[i] }' file1 file2

thanhdat · #3 (**permalink**) 08-27-2009

or use grep :

Code:

grep -v -f fileB fileA

panyam · #4 (**permalink**) 08-27-2009

Yes ..Your right , no need to go for awk , if we can do in a simple grep statement.

My mind always strikes to work using awk ..

rdhanek · #5 (**permalink**) 08-27-2009

Hi Panyam/thanhdatI am unable to use grep -v -fas it is giving me the error below.

Code:

grep: illegal option -- fUsage: grep -hblcnsviw pattern file . . .

And the awk that has been specified is giving a blank space once the lines are deleted and the data is not coming in the same order as it is originally. For example, last line is coming inthe middle and vice versa. In my script, it should not change the order of the lines in the output.Please help. And let me know if you need more details.I am using SUN OS box.

panyam · #6 (**permalink**) 08-28-2009

Not sure , why grep -v -f option is not working .

Try some thing like this :

Code:

awk 'NR==FNR { a[$0]=$0;b[++n]=$0;next } { if($0 in a) {a[$0]="";}} END { for (i=1;i<=n;i++) print a[b[i]] }' file1 file2 | sed '/^$/d'

More UNIX and Linux Forum Topics You Might Find Helpful
Thread	Thread Starter	Forum	Replies	Last Post
Remove lines based on contents of another file	bashshadow1979	Shell Programming and Scripting	4	03-25-2009 12:32 PM
Delete line in file based on data in another file	earth_goddess	Shell Programming and Scripting	1	12-29-2008 10:47 AM
Looking for a perl script (windows) to delete the contents of a file	ntgobinath	Shell Programming and Scripting	14	12-23-2008 01:08 PM
sh script that reads/writes based upon contents of a file	rdudejr	Shell Programming and Scripting	3	07-12-2006 11:38 AM
i want to delete a file based on existing file in a directory	srivsn	Shell Programming and Scripting	3	04-11-2006 05:38 AM

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Display Modes	Rate This Thread
Switch to Linear Mode Hybrid Mode Switch to Threaded Mode	Rate This Thread:


	Powered by