Ubuntu 18.04LTS Quick Reference

Install

• Initial installation

  • From https://releases.ubuntu.com/18.04/, download 64-bit PC (AMD64) desktop image, to Downloads/ubuntu-18.04.1-desktop-amd64.iso.
  • Create a bootable USB drive:

    If drive contains data, unmount it: (e.g. umount /dev/sdb1):

    1. Application: Startup Disk Creator:
    2. Source: /home/ray/Downloads/ubuntu-18.04.1-desktop-amd64.iso
    3. To Use: /media/ray/2G-USB
    4. Make Startup Disk

  • Use USB drive to install Ubuntu.

    I used the suggested defaults, including wiping the existing disk and having only one partition.

• Bug fixes

  Get software that Ubuntu can't install by default for legal reasons.

  • # cd /etc
  • # mv resolv.conf resolv.conf.orig
  • # ln -s ../run/systemd/resolve/resolv.conf .

• Extra software

  Get software that Ubuntu can't install by default for legal reasons.

  • # apt install ubuntu-restricted-extras

• Device drivers

  Install device drivers (e.g. for WiFi).

  • Application: software and updates
  • Select additional drivers
  • Select install

Configure

• System files

  Update as necessary based on previous incarnation:

  • /etc/passwd
  • /etc/shadow
  • /etc/hosts
  • /etc/exports
  • /etc/fstab
  • /home

• Sudo

  Change sudo timeout (e.g. to 60 seconds):

  • # visudo
  • - Defaults env_reset
  • + Defaults env_reset,timestamp_timeout=60

• Temp space

  We have lots of RAM, so put /tmp there:

  • • $ vi /etc/fstab
    • + tmpfs /tmp tmpfs rw,nosuid,nodev,noatime 0 0

• Swap space

  • Create a new 8 GB swap file:

    • $ grep SwapTotal /proc/meminfo
    • # swapoff -a
    • # dd if=/dev/zero of=/swapfile bs=1G count=8
    • # mkswap /swapfile
    • # swapon /swapfile
    • $ grep SwapTotal /proc/meminfo
    • SwapTotal: 8388604 kB

  • Reduce the need to swap:

    • $ vi /etc/sysctl.conf
    • + sysctl vm.swappiness=10

• Grub

  • Make the Grub output legible on a 4K screen. (This patch sometimes goes away without warning.)

    • # vi /etc/default/grub
    • - #GRUB_GFXMODE=640x480
    • + GRUB_GFXMODE=640x480

• Desktop

  gnome-tweaks is a graphical interface for configuring the gnome desktop.

  • Focus windows without raising them. There's a lot of room available for the full clock.

    • # apt install gnome-tweaks
    
    
    • Application: gnome-tweaks.
    • Windows: focus-sloppy.
    • Top Bar: date seconds hot-corner.

  • Dock appearance and power settings.

    • Application: settings.
    • Dock: auto-hide, 42%, left.
    • Power: 15 min, Wi-Fi off, Bluetooth off.

  • Make dash icon click minimize all related windows.

    • $ sudo -i
    • root# su gdm -s /bin/bash
    • gdm$ gsettings set org.gnome.shell.extensions.dash-to-dock click-action 'minimize'
    • gdm$ exit
    • root# exit

• Gnome Terminal

  • Add window borders (needed for white-on-black mode).

    • # vi .config/gtk-3.0/gtk.css
    • + decoration { border: 2px solid gray; background: gray; }

• Keyboard

  • Make the pointless CapsLock key work as a Ctrl key.

    • # vi /etc/default/keyboard
    • + XKBOPTIONS="ctrl:nocaps"

  • Make NumLock stay on at boot time.

    • $ sudo -i
    • root# su gdm -s /bin/bash
    • gdm$ gsettings set org.gnome.settings-daemon.peripherals.keyboard numlock-state 'on'
    • gdm$ exit
    • root# exit

  • Set the compose key (for ~/.XCompose).

    • $ gnome-tweaks
    
    
    • Keyboard & Mouse
    • Compose Key: Menu

Update

• Packages

  Fetch latest list of software packages, and then upgrade those that need it.

  • # apt update
  • # apt upgrade

System

• Syslog

  • cron

    Enable the crontab log.

    • # vi /etc/rsyslog.d/50-default.conf
    • < #cron.* /var/log/cron.log
    • > cron.* /var/log/cron.log

  • gsd-housekeeping

    gsd-housekeepin[2188]: Failed to enumerate children of /tmp/systemd-private-...: Error opening directory '/tmp/systemd-private-...': Permission denied

    Janne Snabb recommends disabling the service:

    • # cd /usr/lib/gnome-settings-daemon
    • # mv gsd-housekeeping gsd-housekeeping.off

• Mail server

  The cron uses mail to deliver error messages, and complains about "No MTA" if there isn't one.

  • # apt install postfix mailutils

  When the postfix installation asks, select local delivery only.

• SSH Server

  • # apt install openssh-server
  • # ssh-keygen -b 4096 -t rsa
  • # ssh-add
  • # vi /etc/ssh/ssh_config
  • + ForwardX11Trusted yes

• Filesystems

  • Imports

    Find what is available from a server (NFS or SAMBA):

    • $ showmount --exports HOSTNAME
    • $ smbclient --list=HOSTNAME

  • Media Sharing

    • # apt install rygel

    Settings → Sharing → Media):

  • Automount

    If /net exists, references to /net/hostname/directory will automaticaly perform the NFS mount if it is available.

    If /cifs exists, references to /cifs/hostname/folder will automaticaly perform the Samba CIFS mount if it is available.

    • # apt install autofs
    • # vi /etc/auto.master
    • + /net -hosts
    • + /cifs /etc/auto.smb --timeout=300
    • # /etc/init.d/autofs reload

  • Samba

    If Windows shares aren't being detected, StackExchange suggests adding this line:

    • # vi /etc/samba/smb.conf
    • + client max protocol = NT1

  • NFS

    • NFS Server

      • # apt install nfs-kernel-server
      • # mkdir /export
      • # vi /etc/exports
      • + /export 192.168.1.0/24(rw,nohide,insecure,no_subtree_check,async)
      • # vi /etc/hosts.deny
      • + rpcbind mountd nfsd statd lockd rquotad : ALL
      • # vi /etc/hosts.allow
      • + rpcbind mountd nfsd statd lockd rquotad : 127.0.0.1, 192.168.0.10
      • # service nfs-kernel-server restart

    • NFS Client

      • # apt install nfs-common
      • # mount -t nfs -o proto-tcp,port=2049 192.168.0.10:/export/... /mnt/...
      • # vi /etc/fstab
      • + latitude-d830:/export/backups/ray-desktop /mnt/latitude-d830/backups nfs rw,auto,noatime,nfsvers=4 0 0

  • SD Card

    • # apt install exfat-fuse exfat-utils
    • # apt install gparted

  • Android

    • # apt install jmtpfs
    • $ jmtpfs ~/mnt/AngiePhone

• Monitoring

  • hardware

    • # lshw -c multimedia

  • sensors

    • # apt install lm-sensors
    • # sensors-detect
    • # /etc/init.d/kmod start
    • $ sensors
    • iwlwifi-virtual-0
    • Adapter: Virtual device
    • temp1: N/A
    •  
    • coretemp-isa-0000
    • Adapter: ISA adapter
    • Package id 0: +46.0°C (high = +100.0°C, crit = +100.0°C)
    • Core 0: +46.0°C (high = +100.0°C, crit = +100.0°C)
    • Core 1: +45.0°C (high = +100.0°C, crit = +100.0°C)
    •  
    • pch_skylake-virtual-0
    • Adapter: Virtual device
    • temp1: +47.5°C

  • ifconfig

    • # apt install net-tools

  • dconf-editor

    • # apt install dconf-editor

  • iostat

    • # apt install sysstat
    • $ iostat | grep -v "loop"
    • Linux 4.15.0-42-generic (ray-desktop) 2018-12-09 _x86_64_ (4 CPU)
    •  
    • avg-cpu: %user %nice %system %iowait %steal %idle
    • 3.54 0.01 0.90 0.18 0.00 95.36
    •  
    • Device tps kB_read/s kB_wrtn/s kB_read kB_wrtn
    • sda 5.73 20.54 211.40 1919230 19752713
    • sdb 0.04 0.21 0.47 19965 43800

• Backups

  • Deja-dup

    This method is good for convenient restores using the Files GUI, but it uses a lot of space, and the saved data is not kept in a format that is easily acessible by other means.

    • # apt install deja-dup
    • # apt install duplicity
    • # apt install python-gi

  • Rsync

    This method allows quick restores and version comparisons by standard CLI commands.

    Run this script once a day from the root crontab:

    • 45 23 * * * root /home/ray/Log/cron-root-night
    • (echo ">>>>>>>>>>>>>>>>>>>>>>>" $(date)
    •   today=$(date +%Y-%m-%d)
    •   month=$(date +%Y-%m)
    •   # USB backups
    •   cd /media/ray/Backup-Ray
    •   rsync --archive --one-file-system --delete --backup --backup-dir="../../$today/etc" "/etc/" "mostrecent/etc/"
    •   rsync --archive --one-file-system --delete --backup --backup-dir="../../$today/home" --exclude=".config/google-chrome/" --exclude=".cache/" --exclude=".local/share/zeitgeist/" --exclude="Downloads/" "/home/" "mostrecent/home/"
    •   rsync --archive $today/ $month/
    •   echo "<<<<<<<<<<<<<<<<<<<<<<<" $(date)
    • ) &>>/home/ray/Log/root.out

    The available versions are easy to find:

    • $ ls -l {,*}/home/ray/.viminfo
    • -rw------- 1 ray ray 37633 Dec  7 22:38 2018-12-08/home/ray/.viminfo
    • -rw------- 1 ray ray 37462 Dec  8 18:56 2018-12-09/home/ray/.viminfo
    • -rw------- 1 ray ray 41202 Dec 10 08:15 2018-12-10/home/ray/.viminfo
    • -rw------- 1 ray ray 37700 Dec 10 15:26 2018-12-11/home/ray/.viminfo
    • -rw------- 1 ray ray 37700 Dec 10 15:26 2018-12/home/ray/.viminfo
    • -rw------- 1 ray ray 45492 Dec 11 16:46 mostrecent/home/ray/.viminfo
    • -rw------- 1 ray ray 45325 Dec 12 15:49 /home/ray/.viminfo

    The monthly consolidations (e.g. 2018-12) can be retained for a while, and the daily backups deleted as necessary after a few months.

• Printing

  • Print queue

    Jobs more than 3 hours old are automatically cleaned from print queues. Change the 10800 seconds default to 0 seconds to disable this feature:

    • # vi /etc/cups/cupsd.conf
    • + MaxJobTime 0

  • Scanner

    sane-utils is for a scanner. Version numbers might vary.

    • # apt install smbclient
    • # apt install sane-utils
    • # ln -s /usr/lib64/sane/libsane-brother3.so.1.0.7 /usr/lib/x86_64-linux-gnu/sane/libsane-brother3.so.1

• Events

  To test input events and devices:

  • # apt install evtest
  • # evtest
  • No device specified, trying to scan all of /dev/input/event*
  • Available devices:
  • /dev/input/event0: Sleep Button
  • /dev/input/event1: Power Button
  • /dev/input/event2: Power Button
  • /dev/input/event3: Video Bus
  • /dev/input/event4: Microsoft Microsoft 3-Button Mouse with IntelliEye(TM)
  • /dev/input/event5: Das Keyboard
  • /dev/input/event6: Das Keyboard
  • /dev/input/event7: Dell Dell AC511 USB SoundBar
  • /dev/input/event8: ITE8708 CIR transceiver
  • /dev/input/event9: HDA Intel PCH Front Headphone
  • ...
  • Select the device event number [0-14]: 8
  • Input driver version is 1.0.1
  • Input device ID: bus 0x19 vendor 0x1283 product 0x0 version 0x0
  • Input device name: "ITE8708 CIR transceiver"
  • Supported events:
  • Event type 0 (EV_SYN)
  • Event type 1 (EV_KEY)
  • Event code 28 (KEY_ENTER)
  • Event code 103 (KEY_UP)
  • Event code 105 (KEY_LEFT)
  • ...
  • Event code 523 (KEY_NUMERIC_POUND)
  • Event type 4 (EV_MSC)
  • Event code 4 (MSC_SCAN)
  • Key repeat handling:
  • Repeat type 20 (EV_REP)
  • Repeat code 0 (REP_DELAY)
  • Value 500
  • Repeat code 1 (REP_PERIOD)
  • Value 125
  • Properties:
  • Testing ... (interrupt to exit)

• Infrared

  To access the Consumer InfraRed sensor:

  • # apt install ir-keytable
  • $ ir-keytable --verbose --test

• Google Phone

  To allow Chrome to access phone dialer.

  • $ vi ~/.local/share/applications/mimeapps.list
  • + x-scheme-handler/tel=hangouts.desktop
  • $ vi ~/.local/share/applications/hangouts.desktop
  • + #!/usr/bin/env xdg-open
  • + [Desktop Entry]
  • + Exec=bash -c 'xdg-open "https://hangouts.google.com/?action=chat&pn=${0//tel:/}"' %u
  • + Terminal=false
  • + Type=Application

Software

• Programming

  • Compilers

    • # apt install gcc

  • Editors

    • # apt install vim
    • $ vi .vimrc
    • + if has("autocmd")
    • + filetype plugin indent on
    • + endif

  • CLI

    • For the jot command:

      • # apt install athena-jot

    • For the urlencode command:

      • # apt install urlencode

    • For the jq command:

      • # apt install gridsite-clients
    • For UW/MFCF commands, copy:
      • align
      • decomment
      • lc
      from: Ray's program source into ~/bin/. Remove ".py" suffixes and in case of namespace conflict, rename as appropriate.

• Web

  • Chrome

  • Extensions

    AdBlock

    Suppresses advertising.

    Copy as Markdown

    Converts URL to Markdown.

    Perapera Chinese

    Provides pop-ups for Chinese characters.

    Enable Copy

    Re-enables disaled right-click.

• Files

  • Jpeg files

    For displaying jpeg metadata.

    • # apt install exiftags
    • $ exiftags file.jpeg

  • MP3 files

    For displaying mp3 metadata.

    • # apt install mp3info
    • $ mp3info file.mp3
    •  
    • # apt install easytag
    • $ easytag &

Coding

Most of these are of the everyone knows that category. But when one does something only once a year or so, it's nice to have a reminder that one really does know it.

• CLI

  • Dates

    • Format ctime:

      • $ date --date="@-545693400" +"%F %H:%M %z"
      • 1952-09-15 22:30 -0400

  • File systems

    • Show drives and partitions:

      • $ lsblk
      • NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
      • loop0 7:0 0 89.5M 1 loop /snap/core/6034
      • loop1 7:1 0 2.3M 1 loop /snap/gnome-calculator/260
      • ...
      • loop15 7:15 0 3.7M 1 loop /snap/gnome-system-monitor/51
      • sda 8:0 0 465.8G 0 disk
      • ├─sda1 8:1 0 512M 0 part /boot/efi
      • └─sda2 8:2 0 465.3G 0 part /
      • sdb 8:16 1 57.8G 0 disk
      • └─sdb1 8:17 1 57.8G 0 part /media/ray/Backup-Ray

• Bash

  • Redirection

    • Expand file into command line:

      If file is guaranteed not to contain whitespace:

      • $ cmd ... $(<file) ...

      If file might contain whitespace:

      • $ xargs <file --delimiter=$'\n' --replace='%' cmd ... % ...

      (% is any character not contained in the ...s.)

• Python

  • Importing

    • from other files

      • import sys
      • sys.path.insert(0, "../../source/myprogsource")
      • from myprogsource import myprog
      • myprog.prog(args)
      (myprogsource/myprog.py)

  • Google Spreadsheets

    • Google

      • See Twilio directions for how to configure Google.

    • Packages

      • # apt install python3-pip
      • # pip3 install gspread oauth2client
      • # pip3 install networkx

    • Code

      • import gspread
      • from oauth2client.service_account import ServiceAccountCredentials
      • scope = ["https://spreadsheets.google.com/feeds"]
      • credentials = ServiceAccountCredentials.from_json_keyfile_name("client_secret.json", scope)
      • client = gspread.authorize(credentials)
      • sheet1 = client.open("Name of Sheet").sheet1
      • sheet1.get_all_values()