Ttdfjt

I'm trying to add columns to a csv file from multiple files. This is what I have tried so far, but keep ending up with either an empty file or just the column from the last file.

 while read i; do
 awk 'print $4' $i.txt > $i_temp
 awk 'NR==FNRa[NR]=$0;nextprint a[FNR],$0' OFS=, test.csv $i_temp >> test.csv
 done < file_list

The file list is just a list of accession numbers:

NA123
NA124
NA125
...

The text files that they correspond to have 4 columns in them, and I want to copy the last column and add it as the next column in a csv file. The contents of the files look like this:

NA123.txt:
April-18 10:00 18:00 8
April-19 09:00 19:00 10
April-20 11:00 16:00 5
...
NA124.txt:
April-18 14:00 18:00 4
April-19 09:00 15:00 6
April-20 07:00 16:00 9
...
NA125.txt:
April-18 10:00 22:00 12
April-19 09:00 12:00 3
April-20 06:00 16:00 10
...

test.csv:
0,
1,
2,
...

I would like the output to be:

0,8,4,12
1,10,6,3
2,5,9,10
...

What do I need to change about this or is there a more efficient way to do this?

Maybe you could try to use paste and one additional temp file

touch temp

while read i; do
 awk 'print $4' $i.txt > $i_temp
 paste temp $i_temp > test.csv
 cp test.csv temp
done < file_list

rm temp

try:

 <file_list xargs -I % awk '
 system("sed -i ''' " NR "s/,\?$/," $4 "/''' test.csv" ) ' %.txt

the xargs is reading filename from file_list file and feed to awk thought xarags's variable called % with .txt suffix as filename contains.

with sed '#s/$/something/' test.csv" command that used to append something at the end $ of a specific line number # in a file like test.csv; so at above, $4 is the string that need to appended to specific line number taking from NR; ,?$ is saying might your line ends with comma , which I used because you have it in your test.csv. this sed command is calling by awk's system() function.

note that sed is writing in-place any changes, so you will not notice terminal ouput, do:

$ cat test.csv
0,8,4,12
1,10,6,3
2,5,9,10

Why not just use paste?

$ cat in1; cat in2
row1,col2,col3
row2,col2,col3
row3,col2,col3
row4,col2,col3
row1
row2
row3
row4
$ paste -d, in1 in2
row1,col2,col3,row1
row2,col2,col3,row2
row3,col2,col3,row3
row4,col2,col3,row4