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deleting lines by number

 
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# 1  
Old 02-12-2004
deleting lines by number
Is it possible to delete lines by their number? Also, I'd like to delete the last 3 rows of a file too. So from the front and back. Thanks.
# 2  
Old 02-12-2004
use perl.

read the file into an array and push undef into the line you want to delete.

to ditch the last 3 lines use the variable $#array_name (this is a numerical value of the total # of elements in the array) and use pop to get them off the stack.
# 3  
Old 02-12-2004
I haven't used perl before....but I need to get this done today. Is there another way?
# 4  
Old 02-12-2004
I just actually need to delete the first two and last three rows. Any solutions?
# 5  
Old 02-12-2004
I was messing around with this quite a bit.. I think something more efficient could be made in awk, but this'll do for now: Smilie
Code:
count=0
lines=`wc -l < "$3"`
((footer=lines-$2))

for LINE in `cat "$3"`; do
  ((count+=1))
  if [[ $count -gt $1 && $count -le $footer ]]; then
    echo "$LINE" >> tmpfile
  fi
done

mv tmpfile "$3"

If you want delete two lines from the top of the file and three lines from the bottom of the file, type: script_name 2 3 yourfile
Last edited by oombera; 02-12-2004 at 03:17 PM..
# 6  
Old 02-12-2004
Here it is in awk:
Code:
awk '
BEGIN {
 b=2
 e=3
 i="'"\"`wc -l < yourfile`\""'"
 c=0
}

{
 c+=1
 if (c > b && c <= (i-e))
  print
}
' yourfile

# 7  
Old 02-12-2004
I tried your script, and i had to input the command:
script_name 1 4 yourfile for it to work on my file.
 
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