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I have bash script looping through several files in a directory. The file identifier has been saved as a variable $num. What I would like to do is add $num as another column in my data like in the example below:

ORIGINAL INPUT:

A B C D E
2 79 56 SD L
1 09 67 JK S
9 60 37 KD G
0 10 47 SO E

EXPECTED OUTPUT:

A B C D E id
2 79 56 SD L 1
1 09 67 JK S 1
9 60 37 KD G 1
0 10 47 SO E 1

*in above example, $num = 1

Ultimately, I want to take a subset of lines from each looped file and cat them into a single large file. For me to know which file the line came from, I need the id from $num.

I have tried using awk '{$12 = $num}' filename but this does not work at all.

Please help!

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2 Answers 2

Reset to default
1

try (awk can be in one line)

 id=...
 awk -v id=$id 'NR==1 { x=NF+1 ; $x = "id" ; print ; }
                NR > 1 { x=NF+1 ; $x = id ; print ; } ' file > new_file

where

  • -v id=$id paste id from shell to awk, if id has funny char, use -v id="îd"
  • NR == 1 , NR > 1 select first, other line
  • { x=NF+1 ; $x = id ; print ; } push $id ( id in awk )
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  • Works perfectly! Commented Oct 26, 2015 at 15:52
0

The following sed script assumes that the field separator is a space. If it's a tab, change the space in both s/// sed commands to \t.

The first line has id appended, second and subsequnt lines have $num appended.

$ num=1
$ sed -e "1 s/$/ id/ ; 2,$ s/$/ $num/" input.txt 
A B C D E id
2 79 56 SD L 1
1 09 67 JK S 1
9 60 37 KD G 1
0 10 47 SO E 1
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