1

I have 2 files having different number of columns and with huge number of rows:

bash-3.00$ cat fileA 
a1,a2,a3,a4,a5,a6,a7,a8,a9
q,w,,,,y,u,,
a,z,,,,q,n,,
.........................
z,p,,,,w,e,,

PS1: a1 - a9 are the headers separated by comma (,). PS2: dot signs (.) means that there are many lines between the two lines

bash-3.00$ cat fileB 
b1      b2
f       t
a       p
m       n
..........      
m       y
t       o

PS: b1 - b2 are the headers and separated by space.

I want to append the a2 and a6 columns of fileA to the contents of b1 and b2 columns. That is, a2 column will be appended to the b1 column; a6 column will be appended to the b2 column.

So, the output file would be as follows:

bash-3.00$ cat output 
a1,a2,a3,a4,a5,a6,a7,a8,a9
q,w,,,,y,u,,
a,z,,,,q,n,,
.........................       
z,p,,,,w,e,,
,f,,,,t,,,
,a,,,,p,,,
,m,,,,n,,,
.........................
,m,,,,y,,,
,t,,,,o,,,

How can I do that by a simple awk command?

Improve this question
1
  • Can you please post terminal output as formatted text, not as pictures? Commented Jul 31, 2015 at 13:43

2 Answers 2

Reset to default
1

It looks like what you want is to i) append the contents of file1 to file2 and ii) change the format of file2 to match that of file one. That is not what your question is actually asking for but it's what you show in your output. If I misunderstood, please edit your question and clarify.

So, to do that, you could simply do:

awk 'NR>1{printf ",%s,,,,%s,,,\n",$1,$2}' file2 >> file1

That will make file1 the output file. If you want to keep file1, you could do:

( cat file1; awk 'NR>1{printf ",%s,,,,%s,,,\n",$1,$2}' file2 ) > out

Or, you could do the whole thing in awk (this is just a simplified version of Archemar's solution):

awk 'NR==FNR{print; next} FNR>1{printf ",%s,,,,%s,,,\n",$1,$2}' file1 file2 > out
Improve this answer
1

try

awk 'FNR == NR { print ; next ; } 
     NR > FNR && FNR > 1 { 
          split($0,A) ; 
          printf ",%s,,,,%s,,,\n",A[1],A[2] ;  }' f1 f2

(can be in one line, I break it to be more readable)

where

  • FNR == NR { print ; next ; } copy lines from first file
  • NR > FNR && FNR > 1 select line from second file without header
  • split($0,A) ; put two var in an array (A)
  • printf ",%s,,,,%s,,,\n",A[1],A[2] ; and print

edit

tested with f1

a1,a2,a3,a4,a5,a6,a7,a8,a9
q,w,,,,y,u,,
a,z,,,,q,n,,
.........................
z,p,,,,w,e,,

and f2

b1  b2
f   t
a   p
m   n
m   y
t   o

run :

awk 'FNR == NR { print ; next ; } NR > FNR && FNR> 1 { split($0,A) ; printf ",%s,,,,%s,,,\n",A[1],A[2] ;  }' f1 f2

result:

a1,a2,a3,a4,a5,a6,a7,a8,a9
q,w,,,,y,u,,
a,z,,,,q,n,,
.........................
z,p,,,,w,e,,
,f,,,,t,,,
,a,,,,p,,,
,m,,,,n,,,
,m,,,,y,,,
,t,,,,o,,,
Improve this answer
6
  • Thanks for your response but it did not help. The output file seems to be empty: bash-3.00$ awk 'FNR == NR { print ; next ; } > NR > FNR && FNR > 1 { > split($0,A) ; > printf ",%s,,,,%s,,,\n",A[1],A[2] ; }' fileA fileB > output bash-3.00$ cat output bash-3.00$ Commented Jul 31, 2015 at 14:12
  • @Murat that's not what he told you to run. Make sure you copy/paste the solution directly into the terminal. Running what you show in your comment should have produced error messages. Commented Jul 31, 2015 at 14:17
  • edited to add the one line solution. Commented Jul 31, 2015 at 14:18
  • @Archemar why are you splitting $0? awk already does that for you; also, there's no need for NR > FNR, the next does that already. See the version in my answer. Commented Jul 31, 2015 at 14:19
  • @terdon true, as per spliting $0 : I was mislead by commas, and FNR is quiet new in awk. Commented Jul 31, 2015 at 14:22

You must log in to answer this question.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.