Replace second occurrence only - Shell Programming and Scripting

lyoncc · #1 12-26-2007

HPUX /bin/sh (posix)

I have a file as such

cat dog mouse
deer elk rabbit
mouse rat pig

I would like to replace the second occurrence of mouse in this file with mouse2. The rest of the file has to stay exactly as is. I'm not sure exactly where mouse might be (could be first,second,third field).

TIA!!!!!!

frank_rizzo · #2 12-26-2007

Put this code in mouse.awk

Code:

/mouse/{
   mcount++
   if(mcount == 2){
       sub("mouse","mouse2",$0)
   }
}

{print}

awk -f mouse.awk animals.txt

rikxik · #3 12-26-2007

So what happens if the file has this:

cat mouse mouse

frank_rizzo · #4 12-26-2007

Quote:

Originally Posted by rikxik

So what happens if the file has this:

cat mouse mouse

the poster said they wanted the second occurrence. this does that. if you need all occurrences of mouse changed on the line where the second occurrence is found then change sub to gsub.

rikxik · #5 12-26-2007

I think I was not clear. I meant, for "cat mouse mouse", the second "mouse" on this line also counts as a second ocurrance. So shouldn't that change to "cat mouse mouse2"?

DeepakS · #6 12-26-2007

This'll take care of it:

Code:

awk -f mouse.awk RS=" " ORS=" " animals.txt

Code:

$ cat animals.txt 
cat dog pig 
deer elk rabbit
mouse mouse mouse

$ awk -f mouse.awk RS=" " ORS=" " animals.txt 
cat dog pig 
deer elk rabbit
mouse mouse2 mouse

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