Adding to arrays [duplicate]

Question

I have this script

tests=()
igrepy -l $1 . | while read -r line
do
    // some processing
    tests+=("${second[0]}")
done
echo ${tests[@]}

I've checked that 'second' has a result and it does, however my echo returns a blank string. What has gone wrong here? This is on rhel6, 'igrepy' is an alias to a case insensitive grep that only search python files

Answer 1

The problem you are seeing is the standard "pipe creates subshell" with bash.

eg if you do

a=10
echo 100 | read a
echo $a

then a will still be set to 10 with bash.

In your case you have

igreppy | while read ...
do
  ....
done

and all the stuff inside that while loop will be in a subshell.

Instead it can be rewritten using process substitution

while read ...
do
  ....
done < <(igreppy ...)

Now no subshell is created for the while loop.