Sysadmin

It’s always recommended to backup your data for safety, but for safety AND security let’s encrypt your backups! to compress and encrypt with ‘mypassword’: tar -Jcf - directory | openssl aes-256-cbc -salt -k mypassword -out backup.tar.xz.aes to decrypt and decompress: openssl aes-256-cbc -d -salt -k mypassword -in backup.tar.xz.aes | tar -xJ -f - Another trick with the tar command is useful for remote backups: tar -zcvfp - /wwwdata | ssh root@remote.server.com "cat > /backup/wwwdata.tar.gz" ...

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:

Mi e’ capitato di inserire degli script nelle varie directory /etc/cron.daily, /etc/cron.weekly ma di scoprire che questi script non vengono eseguiti. Il motivo e’ che il run-parts usato nelle Debian e derivate ignora i file che contengono un “.” (e quindi tutti quelli con l’estensione) Questo comportamento e’ documentato anche nella man page, e previene alcuni inconvenienti come l’esecuzione dei .bak ma lo scrivo anche qui per ricordarmelo … E forse potra’ essere utile a qualcun altro :) ...