Shell script not reading getopts arguments on MacOS - bash

Question

I have written a script that performs tasks according to switches used on command line. Here is my script:
Expects the git branch name and two optional switches
-r for resetting database
-t for merging training data
test.sh
merge_training=false
reset_database=false
while getopts ":tr" opt; do
case ${opt} in
t ) # process option t
echo "one"
$merge_training=true
;;
r ) # process option r
echo "two"
$reset_database=true
;;
esac
done
echo $reset_database
echo $merge_training
When I run this script with command:
sh test.sh branchname -r -t
It does not print one or two and the last statements prints:
false
false
What is wrong here?

Answer 1

What is wrong is your assignments. Your should have got 2 error messages saying:
false=true: command not found
Hint: Never put a $ on the left-side of an assignment:
The convention is to put options first, then extra parameters, so your command-line should be:
bash test.sh -r -t branchname
Use bash not sh. sh is a POSIX shell and is roughly a subset of bash (its complicated). Don't confuse the two.
merge_training=false
reset_database=false
while getopts ":tr" opt; do
case ${opt} in
t ) # process option t
echo "one"
merge_training=true # <<<<<<<<<<<<<<<
;;
r ) # process option r
echo "two"
reset_database=true # <<<<<<<<<<<<<<<
;;
esac
done
shift $(( OPTIND-1 ))
extra="$1"
echo $reset_database
echo $merge_training
echo $extra

Answer 2

when you remove the branchname as a param, then it works (- but you have to also remove the $ from $merge_training=true, else you try to false=true..)
So what you could do is to save the $1 param in a variable and simply shift.
Here the code:
#!/bin/bash
merge_training=false
reset_database=false
branchname="$1"
shift
while getopts ":tr" opt; do
case $opt in
t ) # process option t
echo "one"
merge_training=true
;;
r ) # process option r
echo "two"
reset_database=true
;;
esac
done
echo $branchname
echo $reset_database
echo $merge_training

Answer 3

Some of the points you could enhance on your script,
Variable assignments don't take $ on the left-hand-side
The command-line arguments are seeing an extra argument branchname before processing the actual OPTSTRING, you need to exclude the first parameter before getting into the getopts() call.
Always set the shell interpreter to the one you want to run your script with. In bash do #!/usr/bin/env bash
Always quote your shell variables unless you have a good reason not to.
The updated script should look like below if you are passing arguments as bash test.sh branchname -r -t
#!/usr/bin/env bash
merge_training=false
reset_database=false
branchname="$1"
shift 1
while getopts ":tr" opt; do
case "${opt}" in
t ) # process option t
echo "one"
merge_training=true
;;
r ) # process option r
echo "two"
reset_database=true
;;
esac
done
echo "$reset_database"
echo "$merge_training"