CODEWITHSUNDEEP
bashshell
user1116360
user1116360

Reputation: 422

Condition usage

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.

Upvotes: 1

Views: 75

Answers (2)

shellter
shellter

Reputation: 37278

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

Upvotes: 1

Roger Lindsj&#246;
Roger Lindsj&#246;

Reputation: 11543

The problem is that the only input is from less which is fully consumed by the awk script. The console is not available.

Would something like this be useful

i=$(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;}' file)
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

Upvotes: 0

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