command line hints

one line magic ;)

loop command

while true; do sleep 3 ; ls -Flh|grep -v total;  done

make a lot of files with random input

while true; do    dd if=/dev/urandom of=tmp.$RANDOM.txt  count=200;  done



check md5
MD5=`md5 -q blabla ` && if [ $MD5 = 66f1a2dc15218b64023fc566fe51f39a ];  then;  echo ok ; else; echo false; fi

check open port
echo -n "GET / HTTP/1.0\r\n\r\n" | nc localhost 80 
or
echo -n "\r\n" | nc  localhost 80 > /dev/null  && echo ok || echo false