Linux

Linux Resources

• LWN
• 0xax Linux Insides
• Linux Containers Ubuntu Server LXC
• Oracle 12c In LXC
• Web Upd8

Linux Boot Process

• Kernel Parameters

Ubuntu

1. Ubuntu Releases
2. Kernel 4.2 for Ubuntu 14.04 “Trusty Tahr”
3. systemd service

GRUB2

• GRUB2 Manual
• Recovering from GRUB crash
• How to scroll in vim
• GRUB CLI
• GRUB2 Displays

Linux Partitions

• Moving Partitions
• Shrink root fs - how to shring root fs without booting a livecd

Linux Utilities

HexEditors

1. StackOverflow on hexeditors
   • wxHexEditor
   • Bless - simple but powerfull.
   • dhex - pretty sophisticated but simple hex editor with a diffmode
2. Viewer
   • od - standard Linux CLI utility. Try it: od -A x -t x1z README.txt.
   • xxd - yet another CLI hex dumper for Linux
   • hexdump - another CLI hex dumper.
   • hte is more than a hex viewer, it is also disassembler, and also kind of multi bin format duper. In Ubuntu installs by apt-get install ht
3. Terminal
   • Gnome Terminator
4. Links
   • Comparision of hex editors
   • Best Linux Hex Editors

The lsblk and similar commands

I consider myself to know Linux well but it still keeps surprising me quite often. Here is the list of commands I discovered recently:

The lsblk command resources:

• Amazon
• RedHat
• Manual

The lsblk example:

oel64|oracle|1034$ lsblk
NAME                        MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda                           8:0    0   500M  0 disk 
└─sda1                        8:1    0   499M  0 part /boot
sdb                           8:16   0 298.1G  0 disk 
├─sdb1                        8:17   0 249.3G  0 part 
├─sdb2                        8:18   0  39.1G  0 part 
│ ├─vg_oel64-lv_root (dm-0) 252:0    0  37.1G  0 lvm  /
│ └─vg_oel64-lv_swap (dm-1) 252:1    0     2G  0 lvm  [SWAP]
└─sdb3                        8:19   0   9.8G  0 part 
sr0                          11:0    1  1024M  0 rom  
oel64|oracle|1035$

1. blkid - displays UUID and LABEL for filesystems.
2. tune2fs - displays and alters details of extX filesystems.
3. btrfstune - similar to tune2fs displays and alters properties of btrfs.
4. iotop
5. perf
6. pv - monitor progress of data through a pipe
7. gdmap - similar to windirstat, shows space distribution in a directory.

Linux and VirtualBox

Transient Folders

In VirtualBox you can access (read-only or read-write) to selected folders and/or disks from the host system. They are called Shared Folders. Among them you can have Machine Folders and Transient Folders. The Machine Folders are mounted automatically by the VirtualBox addon when the guest starts. And the Transient Folders are not to be mounted automatically, by specifically, on request, by the command (generic usage and specific example):

mount -t vboxsf FOLDER_NAME /local_mount_point
mount -t vboxsf D_DRIVE /mnt

Suprisingly I used it more rarely then I wanted to. Instead I copied files there and over to statically mounted machine folders.

Loosing cut-and-paste

Solution, perform the following as the regular user:

killall VBoxClient
VBoxClient-all

Password Generators

• 3 Password Generators For Linux
• 10 Ways to Generate a Random Passwords from CLI
• Web Password Generator
• Password Security

SMB

Goal: To mount a remote filesystems from a Linux box.

classic way

Allows to mount as non-root (mount flag user) and specify credentials in an external file. This mount happens in the kernel layer.

/192.168.0.26/Backup   /mnt/NAS/Backup cifs user,noauto,credentials=/home/iam/.smbpass,uid=iam 0 0

gvfs

gvfs-mount
gvfs-copy
gvfs-ls

FAQ

• Find a broken symlink

Read

1. Red Hat 6.8 Resource Management Guide
2. Cgroups
3. cgroup-v1
4. cgroup-v2
5. Linux Namespaces