Make a diff!
A nice, easy to follow article on how to install Linux alongside Mac OS X, using the rEFInd boot manager:
http://www.howtogeek.com/187410/how-to-install-and-dual-boot-linux-on-a-mac/
I didn’t expect it to be that easy, but OSS has really come a long way.
Nicholas Matsakis of Mozilla on how Rust guarantees type soundness, memory safety, and data-race freedom while still offering control similar to C/C++:
(via Guaranteeing memory safety in Rust | Air Mozilla.)
Rust, with its funny name, reminds more of a mutt than an academic programming language. It’s that pragmatism however, that has a lot of potential to help solving well-known “real world” reliability problems in software engineering. It would definitely make a worthwhile addition to other programming languages taught in CS classes.
Mozilla has already started building Servo, a web browser engine based on Rust. While still far from usable (Disclaimer: I’ve just compiled and quickly tested the current master branch sources on Mac OS X Mavericks), it’s the right strategic move and I wonder when other browser projects, like Chromium, will start shifting to safer programming languages too.
Modern web browsers are very complex and accordingly vulnerable pieces of software and yet, with the rise of the browser as an app platform, we depend more and more on their reliability, safety and security.
Ironically, my Chrome browser irrecoverably froze while I was drafting this blog post. Although chrome doesn’t rust, some Rust would actually be a good thing for Chrome, in the long term.
If you ever need to quickly test an FTPS server, the CLI ftp client http://lftp.yar.ru is quite handy.
After upgrading Debian, OpenDKIM sometimes stops running or fails to properly restart. If you don’t actively monitor your ZCS server, the only way to detect this is either through a growing mail queue of unsent messages or through a note in the ZCS server admin panel.
Usually, manually restarting either OpenDKIM itself or the whole ZCS server once “fixes” the problem:
# service zimbra restart
or
# /etc/init.d/zimbra restart
In other cases, fixing the permissions may help:
# /opt/zimbra/libexec/zmfixperms -verbose -extended
(source)
A friend recently told the following joke:
“The idea that git can be used offline is an illusion – you still need connectivity for googling which arguments to pass to what command.”
That’s an exaggeration, of course, but as always, there’s a grain of truth in it. So here we go:
If you need to delete duplicate e-mail messages on an IMAP server, take a look at this useful IMAP de-duplicator script:
IMAP de-duplicator – IMAPdedup
As IMAPdedup is a command line interface tool (a python script), it’s particularly useful for:
I also found that it deals relatively well with failures (e.g. when a folder is read-only and hence messages can’t be deleted): It simply reports them on the screen and carries on.
Here’s a quick’n’dirty bash script to de-dup the inbox and all subfolders of the specified account:
#!/bin/sh # Delete all duplicate messages in all folders of said account. # Note that we connect through SSL (-x) to the default port. SERVER="my.server.com" USER="mylogin" PASS="mypass" for folder in `imapdedup.py -s $SERVER -x -u $USER -w $PASS -l`; do imapdedup.py -s $SERVER -x -u $USER -w $PASS $folder done
If you only have to de-duplicate messages in a small folder, you could also use the following de-duplication add-on for Mozilla Thunderbird:
Remove Duplicate Messages Add-on for Thunderbird
Note however that the ‘Remove Duplicate Messages’ add-on is intended for interactive use only, not for batch processing. I also noticed that it fails at cleaning big mail folders (e.g. containing 50’000 messages).
Here’s a quick overview how to migrate a ZCS mail server (based on Ubuntu) to a new IP address:
0) Not covered here: Adjusting DNS entries. Make sure you lower the TTLs of the relevant DNS entries a couple of days in advance in order to minimize downtime for clients (e.g. set a TTL of 300 for a 5 minute downtime).
1) Set the new IP address in:
* The relevant DNS entries
* /etc/network/interfaces
* /etc/hosts
* If ZCS runs in a container/VM, don’t forget to adjust its IP address too.
2) If the new IP address is part of a new subnet, make sure to add this new subnet to ZCS’s trusted_networks, otherwise, sending (relaying) messages through ZCS from Zimbra Desktop (or any other mail client) won’t work[1]. This can be set using ZCS’s web admin interface (i.e. https://mail.myserver.com:7071/zimbraAdmin/):
Navigate to “Server settings”, then open the “MTA” tab and set something analogous to the following in “MTA Trusted Networks”:
127.0.0.0/8 w.x.y.z/26
3) Restart networking and the ZCS services (it’s important, as this adjusts the trusted_network setting in ZCS’s amavisd too):
# /etc/init.d/zimbra stop
# /etc/init.d/networking restart
# /etc/init.d/zimbra start
Alternatively, just reboot the server, particularly if it runs in a VM.
Voilà!
Note: The need for the adjustments in step 2) might come as a surprise. Authenticated messages to be relayed through ZCS apparently seem to originate from the external IP address, not localhost/127.0.0.1.
[1] A typical postfix error message might look like:
Delivery Failure Notification: Invalid address: somebody . com.zimbra.cs.mailbox.MailSender$SafeSendFailedException: MESSAGE_NOT_DELIVERED; chained exception is: com.zimbra.cs.mailclient.smtp.InvalidRecipientException: RCPT failed: Invalid recipient somebody@somedomain.com: 554 5.7.1 : Relay access denied
iTerm2, the successor of iTerm, seems to be quite a bit better then the default Mac OS X terminal app:
iTerm2 – Mac OS Terminal Replacement.
If only every Mac OS X app (i.e. Quartz) would also support copy on select, middle button paste and the other X11-like features! [1] Further, I’d love to see a terminal app that disallows pasting (cmd-v) from the keyboard-controlled clipboard completely as this is potentially a very dangerous thing.
[1] Note: It’s possible to emulate X11’s behaviour to some degree using BetterTouchTool. It’s still not the same though as X11 distinguishes between the mouse-controlled buffer and the keyboard-controlled buffer and doesn’t just “paste from the clipboard”. For reference, see:
Eliot from the SaltyCrane blog wrote a nice Django management command that allows to easily trace a Django runserver simply by executing ./manage.py trace runserver. Works great!
Django trace tool, django-trace is [..] a Django management command that uses sys.settrace with other Django management commands. https://github.com/saltycrane/django-trace.
via Notes on tracing code execution in Django and Python « SaltyCrane Blog.