Replacing the perl script by this bash script works: ######################### #!/bin/bash while read ip; do echo $ip >> /tmp/webl echo "OK user=jsv" done ######################### Removing the ' echo "OK user=jsv" ' line from this script results in the same behavior as with the perl script - so it looks like squid is not getting the perl output. I tried to "cheat" by using qx{echo "OK user=jsv"} in the perl script, but it did not work either. It looks to me like the $|=1; is not working and perl is holding the output in the buffer (?!?). BR, Joao S Veiga