Question

I have a file with contents:

$> cat file
1
2
4

Now, I would like to use/run another script, if the differences between the numbers (subtraction) is larger than 1, else exit from the main script.

I tried to do this in the following way, but does not work:

less file \
| awk '\
    function abs(x){return (((x < 0.0) ? -x : x) + 0.0)}\
    BEGIN{i=1;}\
    {new=old;old=$1}\
    {if(abs($1-new)>1)i++;}
    END{if(i>1) print 1; else print 0;}' \
| while read i;do
 if (( ${i} ));then
 echo -n "Would you like to continue? [yes or no]: "
 read yno
   case ${yno} in   
       y )
           echo Continuing...
           ;;
       n )
           echo Exiting...
           ;;
       * )
           echo "Invalid input"
           ;;
   esac
 else echo Cont...
 fi
done

I would expect, that if ${i}==1, then I can make a decision, whether I want to continue or not.

Answer 1

you wrote

I would expect, that if ${i}==1,

Yes, but what if ${i} = “Error on input” or some other value, your statement needs to explicitly state your condition. Also using less to send a file to a pipe is not a standard situation, why not just pass in the filename to awk for processing, i.e.

awk '\
    function abs(x){return (((x < 0.0) ? -x : x) + 0.0)}\
    BEGIN{i=1;}\
    {new=old;old=$1}\
    {if(abs($1-new)>1)i++;}
    END{if(i>1) print 1; else print 0;}' file1 \
  | while read i;do
 if (( "${i}" == 1 ));then
 echo -n "Would you like to continue? [yes or no]: "
 read yno
 . . .

I hope this helps