How to append additional arguments to bash script which already has arguments? - bash

Question

I have a bash script which opens Unity with arguments and builds a library:
#!/bin/bash
UNITY=$1/$2/Unity.app/Contents/MacOS/Unity
[ "$(uname -s)" == "Darwin" ] && $UNITY -buildtarget $3 -nographics -batchmode -upmNoDefaultPackages -serial $4 -username $5 -password $6
I run it like this:
./openUnity.sh $UNITY_EDITORS_PATH $UNITY_VERSION $PLATFORM $UNITY_LICENSE $UNITY_USERNAME $UNITY_PASSWORD
How can I add additional arguments to all content above?
What I would like is:
./openUnity.sh $LIST_OF_ARGS_ABOVE $NEW_ARGUMENTS
-testPlatform %testPlatform% \
-deviceType %deviceType% \
-closeAfterExecution \
-autoTestRun \
-killProcessesAfterExecution
I cannot really add indefinite number of arguments and finish with $20
Arguments need to be added like: ./script.sh $1 $2 due to external software - using Teamcity
Is there any good approach to do it?

Answer 1

If you truly need args passed to the script, then the only solution is to use location-specific arguments. I suspect that you can use the environment though, since that is a primary mechanic in CI, and it uses the existing environment values that are being passed to the script. The only requirement is that those env vars be exported, which is common practice in CI.
Doing things from the environment when possible is great in CI, and it will make this easier for you because it avoids extending the number of location-specific parameters up too high, and lets the script used named variables instead of variables with numeric names.
For your existing script can be refactored like so (I've prepended an echo so we can see what would be run):
$ cat openUnity.sh
#!/bin/bash
set -u # abort on unassigned variable
UNITY="${UNITY_EDITORS_PATH}/${UNITY_VERSION}/Unity.app/Contents/MacOS/Unity"
[[ "$(uname -s)" == "Darwin" ]] && \
echo "$UNITY" \
-buildtarget "$PLATFORM" \
-nographics \
-batchmode \
-upmNoDefaultPackages \
-serial "$UNITY_LICENSE" \
-username "$UNITY_USERNAME" \
-password "$UNITY_PASSWORD"
$ export UNITY_EDITORS_PATH
$ export UNITY_EDITORS_PATH=/Application/Unit.app
$ export UNITY_VERSION=20.0.1
$ export PLATFORM=darwin
$ export UNITY_LICENSE=abc123
$ export UNITY_USERNAME=dade_murphy
$ export UNITY_PASSWORD=hunter2
$ ./openUnity.sh
/Application/Unit.app/20.0.1/Unity.app/Contents/MacOS/Unity -buildtarget darwin -nographics -batchmode -upmNoDefaultPackages -serial abc123 -username dade_murphy -password hunter2
Now, if your additional parameters will always exist, then adding them is simple:
#!/bin/bash
set -u # abort on unassigned variable
UNITY="${UNITY_EDITORS_PATH}/${UNITY_VERSION}/Unity.app/Contents/MacOS/Unity"
[[ "$(uname -s)" == "Darwin" ]] && \
echo "$UNITY" \
-buildtarget "$PLATFORM" \
-nographics \
-batchmode \
-upmNoDefaultPackages \
-serial "$UNITY_LICENSE" \
-username "$UNITY_USERNAME" \
-password "$UNITY_PASSWORD" \
-testPlatform "$testPlatform" \
-deviceType "$deviceType" \
-closeAfterExecution \
-autoTestRun \
-killProcessesAfterExecution
However, if the new args are optional, we would have to conditionally build a set of args to append:
#!/bin/bash
set -u # abort on unassigned variable
# build an array of required args
args=(
-buildtarget "$PLATFORM"
-nographics
-batchmode
-upmNoDefaultPackages
-serial "$UNITY_LICENSE"
-username "$UNITY_USERNAME"
-password "$UNITY_PASSWORD"
-closeAfterExecution
-autoTestRun
-killProcessesAfterExecution
)
# append any optional args if they are found in the environment
[[ -n "${testPlatform}" ]] && args+=(-testPlatform "$testPlatform")
[[ -n "${deviceType}" ]] && args+=(-deviceType "$deviceType")
UNITY="${UNITY_EDITORS_PATH}/${UNITY_VERSION}/Unity.app/Contents/MacOS/Unity"
# Call UNITY and expand the 'args' array into arguments
[[ "$(uname -s)" == "Darwin" ]] && echo "$UNITY" "${args[#]}"
/Application/Unit.app/20.0.1/Unity.app/Contents/MacOS/Unity -buildtarget darwin -nographics -batchmode -upmNoDefaultPackages -serial abc123 -username dade_murphy -password hunter2 -closeAfterExecution -autoTestRun -killProcessesAfterExecution
$ export deviceType=microwave
$ export testPlatform=irix
$ ./openUnity.sh
/Application/Unit.app/20.0.1/Unity.app/Contents/MacOS/Unity -buildtarget darwin -nographics -batchmode -upmNoDefaultPackages -serial abc123 -username dade_murphy -password hunter2 -closeAfterExecution -autoTestRun -killProcessesAfterExecution -testPlatform irix -deviceType microwave