1

I am trying to take a text file called 'input', of the form

line1 
line2
line3
PATTERN
x y z
x y z
lineN

and use awk to place a number (1) after each "x y z" line. I need the lines before the PATTERN and after the "x y z' lines (lineN) in the output. The output I needs looks like this:

line1
line2
line3
PATTERN
x y z   1 
x y z   1
lineN

What I have so far is:

awk '/PATTERN/ {getline; print $0 "   1" }' < input > output

This gives:

x y z   1

Is it possible to set up a loop to get awk to append an arbitrary number of "x y z" lines or stop after the "x y z" type lines finish?

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2
  • I edited to look more file like. do you need remplacement after PATTERN (and x y z might be 1 2 3 or foo what ever) or editing only line with x y z ?
    – Archemar
    Mar 4, 2015 at 11:09
  • Thank you, I didn't know how to represent it in the fashion you have changed it to. Yes replacement after the PATTERN is found. x y z are just three columns only the lines with x y z should be appended if possible.
    – Christopher
    Mar 4, 2015 at 11:13

2 Answers 2

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1

The looping can help:

awk '/PATTERN/{print;getline;while(!/lineN/){$(NF+1)="  1";print;getline}}1'

Or to extend @Janis idea:

awk '/lineN/{f=0}f{$(NF+1)="  1"}/PATTERN/{f=1}1'
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0
1

You are saying that only the literal "x y z" lines after PATTERN shall be replaced.

awk '
  /PATTERN/ { f=1 }
  f && /x y z/ { print $0, 1 ; next }
  { print }
'

If it's lines with three arbitrary fields then use

awk '
  /PATTERN/ { f=1 }
  f && NF==3 { print $0, 1 ; next }
  { print }
'
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4
  • If OP wants to print lines after PATTERN and before lineN (as one block) you have to add f=0 after block finish.
    – Costas
    Mar 4, 2015 at 11:38
  • Costas, the OP's sample as presented did not suggest that lineN is a pattern like "PATTERN" that terminates a block; as described it's just a continuation of the data line1, line2, ..., lineN, or so it seems at least.
    – Janis
    Mar 4, 2015 at 11:42
  • lineN can have 3 fields too... In any way OP should some how indicate difference between x y z and lineN to fix position where script should stop to add 1
    – Costas
    Mar 4, 2015 at 11:51
  • Indeed the actual requirements would need clarification. I'm sure the OP will come back to ask if necessary once he switches from his sample data to the real data.
    – Janis
    Mar 4, 2015 at 11:55

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