ALE / KSU-IEEE

• email lists - General, Jobs, Study http://ale.org/
• IRC #ale on Freenode
• Meetup.com - “ale linux atlanta” search
• Weekly Sunday Meetings (NW - Smyrna)
• Weekly Tuesday Meetings (SW - Fairburn)
• Monthly Tueday Meetings (Decatur Makers)

Patch that sh/t and keep your piles on some other storage

Thanks for coming out!

Blog: blog.jdpfu.com
email: DJPfulio -@- jdpfu.com – JD (former rocket scientist)
We are 100% Volunteers.

Any Questions?

• Any questions about the reading assignments?
  • Linux for Windows Users
  • Linux is NOT Windows
• You've been using Linux for a week now.
• Any Questions?

I'll make mistakes.

• There are usually 50-500 different ways to solve anything
• I will know a few, but definitely NOT all of them.
• I’d guess I know about 10% of “Linux” after 24 yrs
• At this level, have to provide guidelines and may loose 100% techincal accuracy

Linux for Windows Users

• Linux for Windows Users
• Most things are case-sensitive; programs should handle it, but some do not
• Don't download, manage, install programs like Windows.
• Use a Repo - from a reputable source
• Best to avoid spaces/weird characters in file and directory names.
• Never forget that all Unix-like OSes are multi-User
• Weekly patching and Daily Backups

No GUI Stuff Here

Power Users

• GUIs are slow.
• GUIs cannot be easily automated. Inconsistent.
• GUIs don't work on Servers. Why learn stuff twice?
• No certifications for GUIs. There are for Servers.
• The CLI/Shell is repeatable.
• GUIs change every 2 yrs.

RTFM and Google Everything

• No spoon feeding here.
• Expect you can find answers yourself.
• Hard part is asking the question in the Linux-way / Unix-way.
• None of the software we discuss will be commercial (will be F/LOSS)
• Paid software is a Microsoft and Apple thing, not so much on Linux.
• Google-Fu: ubuntu 16.04 {issue}

Patching

• Do it weekly.
• Reputable distros will have something to patch at least that often.
• Usually, no reboot is needed, but ... if there is a new kernel, reboot.
• Rebooting is for Windows or new kernels (mostly).

Distro Releases Explained

• Ubuntu LTS = 3 or 5 Years of Support
• Debian "Stable" means ~2+ yrs of support
  • Unstable - bleeding edge
  • Testing - will be the next stable ... eventually.
• CentOS - follow RHEL support … in general, moving from 7.1 → 7.2 → 7.3
  • CentOS 7 - June 30, 2024
  • CentOS 6 - 2020
• Fedora - bleeding edge
  • 350-450 days of patches
  • expected to move to the next release when available
  • Redhat CEO uses Fedora 26

Weekly Patching - Debian/Ubuntu

• Ubuntu
  • $ sudo apt update && sudo apt upgrade
  • $ sudo apt update && sudo apt full-upgrade # replaces old packages
• Debian
  • $ sudo apt update && sudo apt upgrade
  • $ sudo apt update && sudo apt full-upgrade # replaces old packages
• Can enable automatic security patches.
• What might the downsides be?

Neomenclature

• $ - normal userid
• # - root userid
• If I use terms you don't know - ASK

Weekly Patching - CentOS/Fedora

• Fedora
  • # dnf upgrade
• CentOS/RHEL
  • # dnf upgrade

• Automatic Updates:
  • dnf install dnf-automatic
  • /etc/dnf/automatic.conf

Linux Logs – When Things Fail

• Always check the log files.
• In /var/log/* - text files.
• sudo egrep -i 'error|warn' /var/log/*log
• systemd uses binary logs, but today those are converted to text for backwards compatibility.

Backups

• Basic Skill
• 2 Types of backups
  • Clone/mirror
  • Versioned

• Stored in 3 physical locations
• Network and storage efficient
• Encrypted
• Automatic
• Restore must be tested. Hope is not a plan.

Virtual Machine Backups

• File → Export Appliance
• This is a clone.
• Very Inefficient.
  • Storage waste
  • Time waste
• Only works with VMs
• Need 2 things – the VM settings and the virtual hard disk.

Baby Physical Machine Backups

• Works for virtual machines too.
• Can clone using clonezilla, partimage, dd, ddrescue, fsarchiver.
• Mirror files using rsync – 1 copy

Expert Physical Machine Backups

• Automatic (if no GUI is uses via crontab)
• Very efficient
• 30 days is 1.15x the original size – 10G → 15G for 30 days of daily backups
• 50 different solutions

Backups – What Needs to be Backed Up?

• Data is NOT enough.
• files, permissions, ownership, groups
• Might want ACLs
• System Settings - partitions, LVs, /etc/, ...
• HOME
• Any system-level data - /var/html/, /var/lib/Dbs…
• Perhaps a list of installed Packages

Backups – Some Tools

• GUIs
  • Aptik
  • Deja-Dup / Duplicati
• Shell / CLI – can be automated
  • Duplicity
  • rsync (with hardlinks to get versioning)
  • rdiff-backup
  • 50 others
• Avoid ‘tar’ and similar tools for over 500MB of files
• Be careful which file system is used for the backups.

Backups – An Example

 # rdiff-backup --exclude-special-files \
                  root@some-other-server:/ \
                  /Backups/some-other-server/

• Put that into a script; chmod +x the script.
• setup ssh between the backup-server and the client machines (always "PULL")
• Run the script from a root crontab - 2am is a good time

Next Topic

• Basic Unix Permissions

Every Saturday until mid-November

• except Oct 14th and Nov 18th
• 10a until noon-ish
• 5 min break around 11a.

Feedback?

Email me or let your IEEE team know.

Linux Runs Everywhere

• Tiny $5 computers
• 1,000 node supercomputers
• smartphones
• tablets
• video players
• desktop and servers

Linux History (Quick)

• Linus
• Usenet Post in 1991

Unix Philosophy

Peter H. Salus said:

• Write programs that do one thing and do it well.
• Write programs to work together.
• Write programs to handle text streams, because that is a universal interface.

Mike Gancarz said:

• Small is beautiful.
• Make each program do one thing well.
• Build a prototype as soon as possible.
• Choose portability over efficiency.
• Store data in flat text files.
• Use software leverage to your advantage.
• Use shell scripts to increase leverage and portability.
• Avoid captive user interfaces.
• Make every program a filter.

Linux Applications

• LibreOffice
• Browsers - Chromium/Firefox/Lynx/Opera/ ... 30 others
• Image Viewers - geeqie
• Video Players - vlc, smplayer, mpv, totem, ffmpeg
• Email - Thunderbird, mutt, alpine, ...
• Image Manipulation - Gimp, Imagemagick, ...
• AlternativeTo.net
• To be more efficient, think in the Unix-way.

More than 1 Way, usually 50-500 ways

• User is KING!
• Users are expected to build tools to solve problems, using other
  tools.

Where are Things Usually - File System Hierarchy
/home
/
/etc
/root
/bin
/usr

Where Am I?

• pwd
• cwd
• whereis

Listing Files/Directories

• ls
• ls -R
• tree

Viewing Files

• more / less
• cat
• editors ... vi, nano, gedit, kate, geany

Copying, Moving, Renaming Files

• cp, rsync
• mv
• ??

Finding Files

• locate/updatedb
• whereis
• which
• find

Command Line Editing / Efficiency

• {tab} completion
• arrows
• -arrows
• history

RTFM Already

• man man
• man -k {command} / apropos
• man -s 5 {...}
• man -s 8 {...}

Pattern Matching

• Don't type much
• regex