UNIX for Dummies Questions & Answers

I have a file containing 4 columns.
need to scan that file, if all the rows in the column4 have a value ZERO, it should print "everything is fine".
And if all are not ZERO , at the first encounter of non ZERO value of 4th column it should print "some problem "

may be a silly question, but at current moment.. i am unable to think of anything. please help.

I have used a code that scans each line and says..if its fine or some problem.

Code:

awk '{
  print ($4 == 0 ?  "fine" : "some problem")
    }'  inputfile

I hope, m clear at my point.

Well, it is an edge case, being last. Your thinking is too procedural too soon. Assuming spaces as column separators, then logically, the test is, can you find a line not ending in space-zero? If they are all good, you have to look at all, but if any is bad, that is all you need to see, which is the possibility of less work:

Code:

if grep -vq ' 0$' inputfile
then
 echo "some problem"
else
 echo "everything is fine"
fi

In awk, the procedure is to 1) find the first bad, then print bad message and exit, and 2) at last line (if you survive), print good message. i am not an awk fan, I use sed, and do it as a data transformation:

Code:

sed '
  s/.* [^0]$/some problem/
  t x
  ${
    s/.*/everything is fine/
    t
   }
  d
  :x
  q
 ' inputfile

Code:

awk '$4{print "Some Problem"; e=1;exit 1}END{if(!e)print "fine"}' infile

If you exit, how will you ever test e?

Using exit in awk will take you to the END

Code:

$ awk 'BEGIN { e = 1; exit } END { print e }'
1

Oh, a little exit! That's not making me like awk any better! My sed needed no variable, as bad record processing does a real exit!

Newbie question..
How do you interpret this code?
awk , read column 4, then print "some problem".
But what about checking if the value is zero?