This script is useful to delete old messages in “Junk” mail folders (Spam, Trash) automatically after some days. adapted from these notes to work on debian/postfixadmin/dovecot #!/bin/bash # # itera sulle mailbox cancellando messaggi vecchi # per default, nel cestino 30gg e Spam 15 gg # # MySQL details HOST="127.0.0.1"; USER="put_here_your_mysql_user"; PWD="put_here_your_mysql_password"; MYSQL="/usr/bin/mysql"; # dovecot details DOVEADM="/usr/bin/doveadm"; TEMPFILE=$(/bin/mktemp) # Output sql to a file that we want to run echo "use postfixadmin; select username from mailbox" > $TEMPFILE # Run the query and get the results (adjust the path to mysql) results=$($MYSQL -h $HOST -u $USER -p$PWD -N < $TEMPFILE); # Loop through each row for row in $results do echo "Purging $row Trash and Junk mailbox..." # Purge expired Trash $DOVEADM -v expunge mailbox Trash -u $row savedbefore 30d # Purge expired Spam $DOVEADM -v expunge mailbox Spam -u $row savedbefore 15d done rm $TEMPFILE

a small script to check out the number of processors in your linux machine mandatory sample output:

A quick and dirty way to send a bunch of commands to any ssh device (in my case, Cisco appliances)… create a plain old batch file with commands echoed inside: execute the batch, piping its output to plink.exe (putty command link ssh client): c:\> commands.bat | plink -ssh -l username -pw password 11.22.33.44

Giocando con Sinatra ho avuto l’esigenza di servire una determinata pagina solo con un certa frequenza (tecnicamente un rate-limit); la cosa si puo’ fare installando il middleware Rack:Throttle ma non volevo aggiungere un’altra gemma alle dipendenze… In questo esempio se al server arriva piu’ di una richiesta in un intervallo di cinque secondi, rispondiamo a tono… SECONDS_BETWEEN_REQUEST=5 enable :sessions def ratelimit? now=Time.new.to_i session['lastrequest']||=0 #inizializza se non presente result=(now-session['lastrequest'])<SECONDS_BETWEEN_REQUEST #passati dall'ultima richiesta ? session['lastrequest']=now # aggiorna return result end get '/' do if ratelimit? return "<h1>sorry, rate limit exceeded!</h1>" end "<h1>hello!</h1>" end