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awk - how to read multiple files

 
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# 1  
Old 05-16-2013
awk - how to read multiple files
Hi, is there a ways to read multiple files in a single awk command?

For example:
Code:
awk -f awk_script file1 file2 file3

I've google it, most of them suggest using FNR. But I don't understand how it works. It will be a great help if someone able to explain it in simple term with some example.
# 2  
Old 05-16-2013
Yes you can it all depends what you wanna do with them?
You can use FNR or if you have more than 3 use FILENAME it will make your code more presentable.. Smilie
This User Gave Thanks to vidyadhar85 For This Post:
KCApple
# 3  
Old 05-16-2013
Quote:
Originally Posted by vidyadhar85
Yes you can it all depends what you wanna do with them?
You can use FNR or if you have more than 3 use FILENAME it will make your code more presentable.. Smilie
Do you mean all i have to do is put the FILENAME in the BEGIN and it will work?

Code:
BEGIN{FILENAME}
{ some script .....}

# 4  
Old 05-16-2013
You might have to go through the man page for more details..
Below is one of the example where I used FILENAME in awk.. As you can see I have used 4 files here, depending upon filenames I had to perform some actions..

Code:
 
awk 'FILENAME=="ROSEIN"{
                        if(length($2)==6){
                                  A[$1]=$2
                 }
  }
     FILENAME=="BKUPORAGLCC20091204"{
                         if(A[substr($0,9,6)]){
               B[substr($0,1,5),A[substr($0,9,6)]]+=substr($0,38)substr($0,21,17)
                  }
        }
     FILENAME=="rosetb.txt"{FS=",";date=$3;C[0$1,$2]=$5}
     FILENAME=="roset1.txt"{FS=",";D[0$1,$2]=$4;E[0$1,$2]=$5;F[0$1,$2]=$6;G[0$1,$2]=$7}
END{
    for (combined in B){
        if(combined != ""){
           split(combined,seperate,SUBSEP)
         if(B[seperate[1],seperate[2]] ~ /-/){
                                          {printf "%010s|%06s|%08s|%015.2f|%012d|%015.2f|%012d|%015.2f|%012d|\n",
                             seperate[1],seperate[2],date,B[seperate[1],seperate[2]],C[seperate[1],
        seperate[2]],D[seperate[1],seperate[2]],E[seperate[1],seperate[2]],
        F[seperate[1],seperate[2]],G[seperate[1],seperate[2]]}
                }
                else{
                             {printf "%010s|%06s|%08s|+%014.2f|%012d|%015.2f|%012d|%015.2f|%012d|\n",
                             seperate[1],seperate[2],date,B[seperate[1],seperate[2]],C[seperate[1],
        seperate[2]],D[seperate[1],seperate[2]],E[seperate[1],seperate[2]],
        F[seperate[1],seperate[2]],G[seperate[1],seperate[2]]}
                }
    }
 }
}' ROSEIN BKUPORAGLCC20091204 rosetb.txt roset1.txt

This User Gave Thanks to vidyadhar85 For This Post:
KCApple
# 5  
Old 05-16-2013
Please ignore my previous post, I should have try first before I ask. Thanks a lot!

---------- Post updated at 03:51 PM ---------- Previous update was at 03:29 PM ----------

Quote:
Originally Posted by vidyadhar85
You might have to go through the man page for more details..
Below is one of the example where I used FILENAME in awk.. As you can see I have used 4 files here, depending upon filenames I had to perform some actions..

Code:
 
awk 'FILENAME=="ROSEIN"{
                        if(length($2)==6){
                                  A[$1]=$2
                 }
  }
     FILENAME=="BKUPORAGLCC20091204"{
                         if(A[substr($0,9,6)]){
               B[substr($0,1,5),A[substr($0,9,6)]]+=substr($0,38)substr($0,21,17)
                  }
        }
     FILENAME=="rosetb.txt"{FS=",";date=$3;C[0$1,$2]=$5}
     FILENAME=="roset1.txt"{FS=",";D[0$1,$2]=$4;E[0$1,$2]=$5;F[0$1,$2]=$6;G[0$1,$2]=$7}
END{
    for (combined in B){
        if(combined != ""){
           split(combined,seperate,SUBSEP)
         if(B[seperate[1],seperate[2]] ~ /-/){
                                          {printf "%010s|%06s|%08s|%015.2f|%012d|%015.2f|%012d|%015.2f|%012d|\n",
                             seperate[1],seperate[2],date,B[seperate[1],seperate[2]],C[seperate[1],
        seperate[2]],D[seperate[1],seperate[2]],E[seperate[1],seperate[2]],
        F[seperate[1],seperate[2]],G[seperate[1],seperate[2]]}
                }
                else{
                             {printf "%010s|%06s|%08s|+%014.2f|%012d|%015.2f|%012d|%015.2f|%012d|\n",
                             seperate[1],seperate[2],date,B[seperate[1],seperate[2]],C[seperate[1],
        seperate[2]],D[seperate[1],seperate[2]],E[seperate[1],seperate[2]],
        F[seperate[1],seperate[2]],G[seperate[1],seperate[2]]}
                }
    }
 }
}' ROSEIN BKUPORAGLCC20091204 rosetb.txt roset1.txt

I've a question about the FILENAME. All my input files is almost similar but the differences is the value.
For example:
File1
Code:
Potato $1
Fried Potato $4
Steam Potato $3

File2
Code:
Steam Potato $9
Potato $4
Fried Potato $1

In the script, I have to calculate all the potatoes prices. I believe the logic is the same for each file. In your FILENAME example, I see that you use different logic for each file. In my case, wouldn't it causes redundant code if I have to repeat the same logic for every files?

I thought it will work if i try to put "||" before each FILENAME. But it didn't work like I expected it.

Code:
FILENAME=="file1" || FILENAME="file2" ....

 
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