Capture output of a command that get stuck

When you pipe a command/application and this one doesn't show any output it should be due to the buffer.

You have two solution (I guess there are more) to can pipe and get an output:

Solution 1: Using unbuffer

unbuffer command_never_ends | egrep -io "MQ_*"
#Or if the 'command_never_ends' does really finish:
list_mqs=("$(unbuffer command_never_ends | egrep -io "MQ_*")")

Solution 2: Using named pipes

#Create the named pipe
mkfifo pipe1
#Redirecting 'command_never_ends' output (stdout,stderr) to named pipe
command_never_ends &> pipe1

When you use this: command_never_ends &> pipe1 the program will not be started until the named pipe pipe1 has been read. So now you will have to do something like this:

#Reading line per line the output of 'command_never_ends'
while read -r line; do 
   egrep -io "MQ_*" <<< "$line"
done < pipe0

You can see my answer about named pipes using a Java application to send data to a pipe.

Note
I tried using stdbuf command but it seems doesn't work. I know that stdbuf and unbuffer work in different ways. If someone knows how can achieve this using stdbuf it should be useful for me too.