How to Compare Two files using shell script

pooppp · 08-04-2008, 08:53 AM

How to compare two files called "A.sh" and "B.sh" in unix shell script and the third file "C.sh" should contains the contents of "B.sh" which r not in "A.sh".

Plz help me

brianmcgee · 08-04-2008, 09:42 AM

Code:

# comm -1 -3 A.sh B.sh > C.sh

pooppp · 08-04-2008, 10:45 PM

Hai,
Above not working..
I want the third file(c.sh) should the contents of second file(b.sh) which will not be in first file(a.sh)

for eg:

a.sh
Hello World

b.sh
Hai john, How r u?
World is full of enthu.

c.sh
Hai john, How r u?
is full of enthu.

Note :In c.sh, the word "World" is not there bcoz tht word is in a.sh..

Plz help...

pooppp · 08-04-2008, 11:27 PM

Sorry..Above one is wrong....

I need script like below,
Script to compare file a & file b, the ouput file c should contains the matched contents of file a & file b

file a

1
2
3
4
-----------

file b

a
b
1
2
3
g
--------------
result

1
2
3
-------------
Plz help me

billymayday · 08-04-2008, 11:39 PM

Try comm -2 a b > c

See man comm

pooppp · 08-05-2008, 12:38 AM

Not working above...
I read man & info of comm..but i m not getting the required things

linuxlover.chaitanya · 08-05-2008, 12:56 AM

comm -3 a.sh b.sh > c.sh

pooppp · 08-05-2008, 01:11 AM

Hai,
I tried with above..its showing wrong as below

a.sh
1
2
3
4

-------
b.sh
1
2
3
---------
o/p
4

I want 1 2 3 in o/p but it giving 4 as o/p

linuxlover.chaitanya · 08-05-2008, 01:24 AM

I tried the same thing. I created a file named 'a' with contents 12345
and file 'b' with contents 123.
This command gave me the common elements of both.

comm -1 a b

pooppp · 08-05-2008, 01:34 AM

Hai above is working but i redirected to another file as

comm -1 a b >> c

while running the cmd every time result is keep on adding to c..i want the current result only...how to do?

is the below script right?
for i in `cat fileA`
do
grep $i fileB
if [ $? -eq 0 ]
then
{
echo $i >> filec
}
fi
done

Its working fine. but the result is keep on adding to filec(o/p file)..how to clear the o/p file

billymayday · 08-05-2008, 02:05 AM

Don't us >> use >

linuxlover.chaitanya · 08-05-2008, 02:05 AM

comm -1 ab b > c
Use single redirector operator. This will not append the new result and rather over write the file.

linuxlover.chaitanya · 08-05-2008, 02:07 AM

OOps!!! seems billymayday and me wrote the post at the same time. same answer....same time.

jiml8 · 08-05-2008, 02:58 AM

I think

comm -1 -2 a.sh b.sh >c.sh

is what you want.

pooppp · 08-05-2008, 03:35 AM

all ur answer r working fine..thnx
but for my script below,

for i in `cat fileA`
do
grep $i fileB
if [ $? -eq 0 ]
then
{
echo $i >> filec
}
fi
done

I don't want to print in screen i.e., instead of echo cmd above, i want to redirect to filec..
The abve script is working fine while using echo..but in filec its showing only last ele..
Plz edit the above script & send me as i need.