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+# Bash Scripting: It's not so bad
+
+This is all the material for my presention on bash scripting for the DevOps
+meetup (2019-05-27). The slides were presented with [mdp][1]
+
+[1]: https://github.com/visit1985/mdp
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+%title: Bash Scripting: It's not so bad
+%author: Cody Hiar
+%date: 2019-05-27
+
+-> Bash Scripting: It's not so bad <-
+=====================================
+
+-------------------------------------------------
+
+# About Me
+
+* Graduated Computer Engineering at U of A
+* SaltStack Certified
+* Now working remotely @ Blendable
+* Vim/Tmux Diehard, also cli in general
+* Interests: Python, Automation, DevOps, Linux
+
+# Where I be
+
+* www.codyhiar.com
+* www.github.com/thornycrackers
+
+# Past Presentations (available on GitHub)
+
+* Scraping with scrapy (YEGSEC)
+* Python Daemons (Edmonton.py)
+* Setting Django up on a VPS (Edmonton.py)
+* Docker (YEGSEC)
+
+-------------------------------------------------
+
+-> Goals <-
+===========
+
+- What's in the Language
+- Some best practices
+- Resources to help
+
+-------------------------------------------------
+
+-> Why bash scripting? <-
+=========================
+
+- Easy win with tools you already have install.
+- Scripts are easy to share between different people.
+- I don't like repeating myself
+
+^
+
+-> When to bash script: <-
+=====================
+
+^
+
+- Everyday. Automate everything. Invaluable for quick throw away scenarios.
+  Scripting is a great way to learn how linux/unix systems in general work.
+
+^
+
+-> When not to bash script: <-
+=========================
+
+^
+
+- Personal Take: If your script is getting past the 100ish line mark it's
+  probably a good time to consider moving to a different language
+
+-------------------------------------------------
+
+-> Bash has it's own language <-
+================================
+
+Bash has support for a bunch of the basic programming features you need such as:
+Variables, Functions, If/Else, Conditionals, Loops, Arrays, Dictionaries, Case
+Switch.
+
+-------------------------------------------------
+
+# Variables
+
+```
+NAME="John"
+```
+
+# Functions
+
+```
+get_name() {
+    echo "John"
+}
+ 
+echo "You are $(get_name)"
+```
+
+# If/Else
+
+```
+if [[ -z "$string" ]]; then
+    echo "String is empty"
+elif [[ -n "$string" ]]; then
+    echo "String is not empty"
+fi
+```
+
+-------------------------------------------------
+
+# Conditionals
+
+```
+git commit && git push
+git commit || echo "Commit failed"
+```
+
+# For Loop
+
+```
+for i in {1..5}; do
+    echo "Welcome $i"
+done
+```
+
+# While Loop
+
+```
+while true; do
+  ···
+done
+```
+
+-------------------------------------------------
+
+-> The "while" poem <-
+======================
+
+
+While true
+do foo
+sleep 1
+done
+
+```
+while true; do clear; curl https://duckduckgo.com; sleep 1; done
+```
+
+-------------------------------------------------
+
+# Array
+
+```
+Fruits=('Apple' 'Banana' 'Orange')
+ 
+echo ${Fruits[0]}  
+```
+
+# Dictionaries
+
+```
+declare -A sounds
+ 
+sounds[dog]="bark"
+ 
+echo "${sounds[dog]}"
+```
+
+# Case Switch
+
+```
+case "$1" in
+  start | up)
+    vagrant up
+    ;;
+ 
+  *)
+    echo "Usage: $0 {start|stop|ssh}"
+    ;;
+esac
+```
+
+-------------------------------------------------
+
+-> My First Bash Script <-
+==========================
+
+1. Run: `touch myscript.sh`
+2. Add the following content
+
+```
+#!/usr/bin/env bash
+echo "Hello World"
+```
+
+3. Run: `chmod +x myscript.sh`
+4. Run: `./myscript.sh`
+
+-------------------------------------------------
+
+-> What can I put in a shell script <-
+======================================
+
+Anything you type into your terminal to run commands can be put into a bash
+script. This means that Bash Scripts are essentially a free way to start
+automating things that you do on a daily basis without having to install any new
+tools.
+
+-------------------------------------------------
+
+-> Example: Postgres Backup <-
+================================
+
+```
+#!/usr/bin/env bash
+ 
+TODAY=$(date +%F)
+FILENAME="database_backup-${TODAY}.sql"
+ 
+if [[ ! -f "$FILENAME" ]]; then 
+    pg_dump -h hostname -U myuser > "$FILENAME"
+fi
+```
+
+-------------------------------------------------
+
+-> Best Practice: Idempotence <-
+================================
+
+Plain English: Output or effect is the same if a script is ran multiple times.
+
+^
+
+This isn't limited to Bash Scripting but is a good practice in other DevOps
+tools you may be using as well.
+
+-------------------------------------------------
+
+-> Best Practice: Unofficial Strict Mode <-
+===========================================
+
+```
+#!/usr/bin/env bash
+#
+# Set options:
+#   e: Stop script if command fails
+#   u: Stop script if unset variable is referenced
+#   x: Debug, print commands as they are executed
+#   o pipefail:  If any command in a pipeline fails it all fails
+#
+# IFS: Internal Field Separator
+set -euxo pipefail
+IFS=$'\\n\\t'
+```
+-------------------------------------------------
+
+-> Best Practice: Traps <-
+==========================
+
+```
+#!/usr/bin/env bash
+function finish {
+  # Your cleanup code here
+}
+trap finish EXIT
+```
+
+Traps are the equivalent of wrapping your script in a giant `try/catch`
+statement so that if anything does fail, the script will clean up after itself.
+
+-------------------------------------------------
+
+-> Best Practice: Linting with Shellcheck <-
+============================================
+
+
+The goals of ShellCheck are
+
+    To point out and clarify typical beginner's syntax issues that cause a
+    shell to give cryptic error messages.
+     
+    To point out and clarify typical intermediate level semantic problems that
+    cause a shell to behave strangely and counter-intuitively.
+     
+    To point out subtle caveats, corner cases and pitfalls that may cause an
+    advanced user's otherwise working script to fail under future
+    circumstances.
+
+https://github.com/koalaman/shellcheck
+
+-------------------------------------------------
+
+-> Best Practice: Automated testing with bats-core <-
+=====================================================
+
+Bats is a TAP-compliant testing framework for Bash. It provides a simple way to
+verify that the UNIX programs you write behave as expected.
+
+https://github.com/bats-core/bats-core
+
+-------------------------------------------------
+
+-> Resources <-
+===============
+
+- https://explainshell.com/
+- https://misc.flogisoft.com/bash/tip_colors_and_formatting
+- https://www.bash.academy/
+- http://redsymbol.net/articles/bash-exit-traps/
+- http://redsymbol.net/articles/unofficial-bash-strict-mode/
+- https://devhints.io/bash
+- https://github.com/jlevy/the-art-of-command-line
+- https://google.github.io/styleguide/shell.xml
+- http://www.bashoneliners.com/
+- https://www.commandlinefu.com
+
+- https://www.codyhiar.com/snippets/awesome-bookmarks-my-collection/
+
+-------------------------------------------------
+
+-> Questions <-
+===============