How to capture the Gradle exit code in a shell script?

Question

I would like to capture the return code of a Gradle task. Here is a small bash script draft which executes a tasks:

#!/bin/bash

gradlew_return_code=`./gradlew assembleDebug`
echo ">>> $gradlew_return_code"
if [ "$gradlew_return_code" -eq "0" ]; then
    echo "Gradle task succeeded."
else
    echo "Gradle task failed."
fi

The script does not store the return value but instead the whole console output of the Gradle task.

---

Please note that the example script is a simplification of a more complex script where I need to capture the return value.

Answer 1

Exit status is in $?. Command substitutions capture output.

./gradlew assembleDebug; gradlew_return_code=$?

...or, if you need compatibility with set -e (which I strongly advise against using):

gradlew_return_code=0
./gradlew assembleDebug || gradlew_return_code=$?

...or, if you need to capture both:

gradlew_output=$(./gradlew assembleDebug); gradlew_return_code=$?
if (( gradlew_return_code != 0 )); then
  echo "Grade failed with exit status $gradlew_return_code" >&2
  echo "and output: $gradlew_output" >&2
fi

Note that I do advise putting the capture on the same line as the invocation -- this avoids modifications such as added debug commands from modifying the return code before capture.

---

However, you don't need to capture it at all here: if statements in shell operate on the exit status of the command they enclose, so instead of putting a test operation that inspects captured exit status, you can just put the command itself in the COMMAND section of your if:

if ./gradlew assembleDebug; then
  echo "Gradle task succeeded" >&2
else
  echo "Gradle task failed" >&2
fi