I finally wrote a guitar tuner in bash. This is the initial commit.

README.md

@@ -1,2 +1,5 @@
 # bashtuner
-A guitar tuner written in bash
+A guitar tuner written in bash.
+To extend, add new tunings to the array. More are coming soon. I may also add other instruments such as the mandolin
+
+Want to support my work? Check out my  [Liberapay page](https://liberapay.com/stormdragon2976), or my membership options on [Patreon](https://patreon.com/stormdragon2976).

bashtuner.sh

@@ -0,0 +1,34 @@
+#!/bin/bash
+
+# Written by Storm Dragon https://social.stormdragon.tk/storm
+# Released under the terms of the WTFPL License http://wtfpl.net
+
+declare -A tuning=(
+  # Dropped 1 step.
+  [6d]="D2 G2 C3 F3 A3 D4"
+  # Standard tuning
+  [6e]="E2 A2 D3 G3 B3 E4"
+)
+
+show_help() {
+  echo "Usage: $0 tune_id"
+  echo "Where tune_id is one of"
+  echo "${!tuning[@]}"
+exit 0
+}
+
+[ $# -ne 1  ] && show_help
+[ -z "${tuning[$1]}" ] && show_help
+# Continuously play the notes until a key is press.
+# Note key can not be enter or space.
+# This will adjust how long each note plays.
+timeout=2
+for i in ${tuning[$1]} ; do
+  unset continue
+  while [[ -z "$continue" ]]; do
+    ps $notePID &> /dev/null && kill $notePID &> /dev/null
+    play -qnV0 synth $timeout pl $i &
+    notePID="$!"
+    read -sn1 -t $timeout continue
+  done
+done