UNIX for Dummies Questions & Answers

I am attempting to pass a string into awk and loop through it, and then for every occurrance of a certain character perform an action. In this case, for example, echo 1 for each time character r is found in the string. Except I can't get it to work. Could someone please tell me why?


echo $string | awk '{
for (i=1;i<=length($0);i++)
do
if (substr($0,i,1) == "r")
echo "1"
fi
done
}'

Code:

if [[ "$string" == *r* ]] ; then
  echo "Found r"
fi ;

Thanks for your reply, but I want it to loop through the string and then perform an action for each occurrance of r, not just once. eg. "rover" would return 11 in this example because there're two r's in it.

I've tried adapting your code so it looks something like this:

echo $string | awk '{
for (i=1;i<=length($0);i++)
do
if [[ (substr($0,i,1) == *r*) ]] ; then
echo "1"
fi ;
done
}'


but get parse errors all over the place:

awk: cmd. line:4: if [[ (substr($0,i,1) == *r*) ]] ; then
awk: cmd. line:4: ^ parse error
awk: cmd. line:4: if [[ (substr($0,i,1) == *r*) ]] ; then
awk: cmd. line:4: ^ parse error
awk: cmd. line:4: if [[ (substr($0,i,1) == *r*) ]] ; then
awk: cmd. line:4: ^ parse error

Any more ideas?

What do you want to do ?

Find the number of occurences of a certain character in a string, or, are you looking for the all the positions where the character appears ?

Hi ,

You are looking for this

Post back if still some problem

Gaurav

Hi Vino,

With due regards, I would like to say that the above may not solve the problem, OP is having. He is looking for no. of occurence of a character in a string. And the above command will give always give output as 1 if there is one or more than one occurence of "r"
Kindly correct me if I am wrong

Gaurav

You are right. It gives 1. -c gives a count of the number of lines where the character occurs.

Good catch.