John's Linux blog

  Introduction The following steps are needed to boot Mac OS under VirtualBox. I tested it using Mac OS X 10.13. I can't guarantee this works. You'll need a source/original mac to copy the OS install. Probably Apple won't approve of this because they want you to buy their original hardware, but sometimes you need hosted VMs in the cloud or similar, and they don't really offer that. Steps Commands below are typed in a command line like the Terminal. 1. On a Mac, do this to download an installer disk: softwareupdate --fetch-full-installer --full-installer-version  ... OR download from the app store. If the operating system you want to install is out of date, ie if the Mac tells you the installer is damaged, set your Mac date and time to however many years ago that operating system came out, and turn of automatic date and time in the date and time system preferences. That way the signature of the installer disk / bundle will still be valid (it is invalid if it is older tha...

If windows updated and wiped your linux bootloader, follow these steps.  https://techblog.dev/posts/2021/12/how-to-fix-missing-grub-boot-menu-after-a-windows-update/  

1. Install: bash$  sudo snap install icloud-for-linux 2. Run one of the apps:   bash$ icloud-for-linux.keynote 3. Drag to your Dock (launcher panel) easy

LVM is the Logical Volume Mapper, which lets you tell Linux that a volume (drive or partition) is part of a group of volumes/drives/partitions, which are considered one drive and which act together as one, called a "volume group".  If you run out of space on a Linux machine and you are using LVM, you can enlarge the drive and make it act as if it were a single drive, by adding another drive and then telling it to add that drive to the LVM volume group. You can tell that your drive is LVM if you see mention of LVM in the output of the "disk free" command, df. Note the wording "dev/mapper" Filesystem                         Size   Used Avail Use% Mounted on udev                               399M     0   399M   0% /dev tmpfs                             ...

 If /var/log/journal is taking up too much space, you can clear it and prevent it growing too big again. Prevention: vi /etc/systemd/journald.conf   Look for: SystemMaxUse=2000M Or similar, and set it to a lower value Then: service systemd-journald restart Clearing once-off: journalctl --vacuum-time=2d assuming for example you want to clear everything before two days ago.

The following script will copy a directory structure from a source to a target and omit files, copying only folders (directories) #!/bin/sh if [ -z "$1" ] ; then echo "Please give a source dir" echo "otherwise I will assume that the source is ".`pwd` echo "Synax: cp-dirsonly.sh sourcedir/ targetdir/" sourcedir="./" fi if [ ! -z "$1" ] ; then sourcedir=$1 fi if [ -z "$2" ] ; then echo "Please give give a target dir" exit fi find $sourcedir -type d -links 2 -exec mkdir -p "$2/{}" \;

Normally to create a network drive you'd use NFS. However, gluster lets you merge multiple network drives into one single drive. I'll post more here as I go.