Thursday, June 23, 2016

converting putty key to open ssh keys

Used the method given here to convert, using
puttygen mykeyfile.ppk -o ~/.ssh/ -O public-openssh
puttygen mykeyfile.ppk -o ~/.ssh/id_rsa -O private-openssh

After moving the keys to .ssh, we also have to chmod 600 or else ssh will not take these keys by default. We also need to name them id_rsa and for ssh to use them by default, without having to specify ssh -i keyname username@server.

fixing dual-boot time differences

With earlier versions of Linux, the method was to choose UTC = yes in /etc/default/rc5 and so on. With Ubuntu 16.04 and above which use systemd, the method is to enter
timedatectl set-local-rtc 1

Monday, June 20, 2016

behaviour of virtualdub frame processing

If we choose Process every other frame (decimate by 2) - the resulting avi would have a framerate half that of the source.

For example, a 30fps source, with this decimate by 2 results in an output at 15 fps. If that 15 fps output is re-saved using direct stream copy choosing 30 fps as output frame rate, then we get a 2x speeded up video. A two-step process.

In order to get 2x speeded up video in one step, choose to Change frame rate to 60 fps, and then Convert to 30 fps.

Tuesday, June 14, 2016

cloning laptop hard disk

My laptop hard disk started showing SMART errors with Crystal Disk Info. Got a new Seagate 1 TB SSHD for replacement. Macrium Reflect Free could not clone - the bad sectors made it abort. Clonezilla did the job in around 4 hours for the 160 GB hard disk with three partitions, using an external USB dock for the new hard disk.

But the cloned hard disk did not boot. Booted with Windows XP install DVD, went into recovery console and did fixmbr. Then XP booted, but showed only C and D drives. Since in any case I would need to copy files from E:, might as well increase the size of C: by deleting D:. Used Partition Wizard for increasing C: size, created D: and E: as fresh partitions, and left free space for Linux. RichCopy copied over the D: and E: contents, ignoring errors, in just about 90 minutes. Now most apps work as expected, except some which complain about path not found - maybe they look for My Documents in C:.

Later, installed Kubuntu 16.04 on a trial basis, using mini.iso and a network install - the process took around 90 minutes.

Tuesday, June 07, 2016

checksums on Windows

As mentioned on this page, installed and tried out WinMD5Sum and Checksums calculator. Found that one of my iso downloads had a checksum error.

Wednesday, June 01, 2016

WHM + CPanel setting up ssh access

To set up shell access via ssh to a server for which I have Web Host Manager (WHM) and CPanel access:

1. Import my existing ssh public key to the server via the CPanel of the relevant user - by clicking Manage SSH keys - for this, as this post mentions, the key should be prefaced with ssh-rsa and should not have line breaks within the key.
2. The key should be authorized - from the Manage SSH keys interface, by clicking on the Manage authorization link. Now ssh login via key exchange using that key would be possible, for that user.
3. In order to get to a root shell, that user has to be added to the wheel group, after making sure that user is in a full shell and not a jailed shell - via WHM in Home >> Account Functions >> Manage Shell Access and Home >> Security Center >> Manage Wheel Group Users respectively.