[SPARK-45497][FOLLOWUP] Simplify symbolic link creation of spark-examples.jar (#73)
### What changes were proposed in this pull request?
Address comments https://github.com/docker-library/official-images/pull/17622#issuecomment-2384397951 from docker official owners
### Why are the changes needed?
Use less fiddly subshell layers in between where things could unintentionally go wrong
### Does this PR introduce _any_ user-facing change?
no
### How was this patch tested?
```
docker run -it --rm scala2.13-java17-ubuntu ls -al /opt/spark/examples/jars | tail -n6
drwxr-xr-x 4 spark spark 4096 Sep 16 04:02 ..
-rw-r--r-- 1 spark spark 232248 Sep 16 04:02 jackson-core-asl-1.9.13.jar
-rw-r--r-- 1 spark spark 780664 Sep 16 04:02 jackson-mapper-asl-1.9.13.jar
-rw-r--r-- 1 spark spark 80424 Sep 16 04:02 scopt_2.13-3.7.1.jar
-rw-r--r-- 1 spark spark 1591043 Sep 16 04:02 spark-examples_2.13-4.0.0-preview2.jar
lrwxrwxrwx 1 root root 38 Oct 8 05:41 spark-examples.jar -> spark-examples_2.13-4.0.0-preview2.jar
```
diff --git a/4.0.0-preview1/scala2.13-java17-ubuntu/Dockerfile b/4.0.0-preview1/scala2.13-java17-ubuntu/Dockerfile
index 169309a..9ee76f6 100644
--- a/4.0.0-preview1/scala2.13-java17-ubuntu/Dockerfile
+++ b/4.0.0-preview1/scala2.13-java17-ubuntu/Dockerfile
@@ -60,7 +60,7 @@
mv sbin /opt/spark/; \
mv kubernetes/dockerfiles/spark/decom.sh /opt/; \
mv examples /opt/spark/; \
- ln -s "$(basename $(ls /opt/spark/examples/jars/spark-examples_*.jar))" /opt/spark/examples/jars/spark-examples.jar; \
+ ln -s "$(basename /opt/spark/examples/jars/spark-examples_*.jar)" /opt/spark/examples/jars/spark-examples.jar; \
mv kubernetes/tests /opt/spark/; \
mv data /opt/spark/; \
mv python/pyspark /opt/spark/python/pyspark/; \
diff --git a/4.0.0-preview1/scala2.13-java21-ubuntu/Dockerfile b/4.0.0-preview1/scala2.13-java21-ubuntu/Dockerfile
index 7f9981a..333324c 100644
--- a/4.0.0-preview1/scala2.13-java21-ubuntu/Dockerfile
+++ b/4.0.0-preview1/scala2.13-java21-ubuntu/Dockerfile
@@ -60,7 +60,7 @@
mv sbin /opt/spark/; \
mv kubernetes/dockerfiles/spark/decom.sh /opt/; \
mv examples /opt/spark/; \
- ln -s "$(basename $(ls /opt/spark/examples/jars/spark-examples_*.jar))" /opt/spark/examples/jars/spark-examples.jar; \
+ ln -s "$(basename /opt/spark/examples/jars/spark-examples_*.jar)" /opt/spark/examples/jars/spark-examples.jar; \
mv kubernetes/tests /opt/spark/; \
mv data /opt/spark/; \
mv python/pyspark /opt/spark/python/pyspark/; \
diff --git a/4.0.0-preview2/scala2.13-java17-ubuntu/Dockerfile b/4.0.0-preview2/scala2.13-java17-ubuntu/Dockerfile
index baaa68a..051acb3 100644
--- a/4.0.0-preview2/scala2.13-java17-ubuntu/Dockerfile
+++ b/4.0.0-preview2/scala2.13-java17-ubuntu/Dockerfile
@@ -60,7 +60,7 @@
mv sbin /opt/spark/; \
mv kubernetes/dockerfiles/spark/decom.sh /opt/; \
mv examples /opt/spark/; \
- ln -s "$(basename $(ls /opt/spark/examples/jars/spark-examples_*.jar))" /opt/spark/examples/jars/spark-examples.jar; \
+ ln -s "$(basename /opt/spark/examples/jars/spark-examples_*.jar)" /opt/spark/examples/jars/spark-examples.jar; \
mv kubernetes/tests /opt/spark/; \
mv data /opt/spark/; \
mv python/pyspark /opt/spark/python/pyspark/; \
diff --git a/4.0.0-preview2/scala2.13-java21-ubuntu/Dockerfile b/4.0.0-preview2/scala2.13-java21-ubuntu/Dockerfile
index 42fc9ec..f2ec53d 100644
--- a/4.0.0-preview2/scala2.13-java21-ubuntu/Dockerfile
+++ b/4.0.0-preview2/scala2.13-java21-ubuntu/Dockerfile
@@ -60,7 +60,7 @@
mv sbin /opt/spark/; \
mv kubernetes/dockerfiles/spark/decom.sh /opt/; \
mv examples /opt/spark/; \
- ln -s "$(basename $(ls /opt/spark/examples/jars/spark-examples_*.jar))" /opt/spark/examples/jars/spark-examples.jar; \
+ ln -s "$(basename /opt/spark/examples/jars/spark-examples_*.jar)" /opt/spark/examples/jars/spark-examples.jar; \
mv kubernetes/tests /opt/spark/; \
mv data /opt/spark/; \
mv python/pyspark /opt/spark/python/pyspark/; \
