diff --git a/CHANGES.txt b/CHANGES.txt
index 69b2ecae81..6e4ee0a460 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -207,6 +207,7 @@
  * Add the ability to disable bulk loading of SSTables (CASSANDRA-18781)
  * Clean up obsolete functions and simplify cql_version handling in cqlsh (CASSANDRA-18787)
 Merged from 5.0:
+ * Do not source cassandra-env.sh unnecessarily in nodetool and other tooling (CASSANDRA-20745)
  * Make source distribution buildable by ant artifacts as doc/scripts/process-native-protocol-specs-in-docker.sh was not executable (CASSANDRA-20802)
  * SSTableIndexWriter#abort() should log more quietly in cases where an exception is not provided (CASSANDRA-20695)
  * Avoid availability gap between UP and queryability marking for already built SAI indexes on bounce (CASSANDRA-20732)
diff --git a/bin/nodetool b/bin/nodetool
index 6ba19e16f0..4ca496b4ea 100755
--- a/bin/nodetool
+++ b/bin/nodetool
@@ -43,20 +43,21 @@ if [ -z "$CASSANDRA_CONF" -o -z "$CLASSPATH" ]; then
     exit 1
 fi
 
-# Run cassandra-env.sh to pick up JMX_PORT
+JMX_PORT=""
+
+# Try to parse port from configure_jmx method call, when not commented out
 if [ -f "$CASSANDRA_CONF/cassandra-env.sh" ]; then
-    JVM_OPTS_SAVE=$JVM_OPTS
-    MAX_HEAP_SIZE_SAVE=$MAX_HEAP_SIZE
-    . "$CASSANDRA_CONF/cassandra-env.sh"
-    MAX_HEAP_SIZE=$MAX_HEAP_SIZE_SAVE
-    JVM_OPTS="$JVM_OPTS_SAVE"
+    jmx_method_call=$(grep "^configure_jmx \+[0-9]\+$" "$CASSANDRA_CONF/cassandra-env.sh")
+    if [ ! "x${jmx_method_call}" = "x" ]; then
+        JMX_PORT=$(echo "${jmx_method_call}" | tr -s " " | cut -d " " -f2)
+    fi
 fi
 
 # In case JMX_PORT is not set (when configure_jmx in cassandra-env.sh is commented out),
 # try to parse it from cassandra.yaml.
 if [ "x$JMX_PORT" = "x" ]; then
     if [ -f "$CASSANDRA_CONF/cassandra.yaml" ]; then
-        JMX_PORT=`grep jmx_port $CASSANDRA_CONF/cassandra.yaml | cut -d ':' -f 2 | tr -d '[[:space:]]'`
+        JMX_PORT=$(grep jmx_port "$CASSANDRA_CONF/cassandra.yaml" | cut -d ':' -f 2 | tr -d '[[:space:]]')
     fi
 fi
 
@@ -111,6 +112,11 @@ if [ "x$MAX_HEAP_SIZE" = "x" ]; then
     MAX_HEAP_SIZE="128m"
 fi
 
+# Sets the path where logback and GC logs are written.
+if [ "x$CASSANDRA_LOG_DIR" = "x" ] ; then
+    CASSANDRA_LOG_DIR="$CASSANDRA_HOME/logs"
+fi
+
 CMD=$(echo "$JAVA" $JAVA_AGENT -ea -cp "$CLASSPATH" $JVM_OPTS -Xmx$MAX_HEAP_SIZE \
             -XX:ParallelGCThreads=1 \
             -Dcassandra.storagedir="$cassandra_storagedir" \
diff --git a/conf/cassandra-env.sh b/conf/cassandra-env.sh
index 8bbf4a592d..50e273517f 100644
--- a/conf/cassandra-env.sh
+++ b/conf/cassandra-env.sh
@@ -291,8 +291,8 @@ configure_jmx()
 # We will be expecting the settings in jmx_server_options and jmx_encryption_options respectively instead.
 # The argument specifies the default port over which Cassandra will be available for JMX connections.
 #
-# If you comment out configure_jmx method call, then JMX_PORT variable will not be set, which means
-# nodetool which sources this file will not see it either and port from cassandra.yaml will be parsed instead,
+# If you comment out configure_jmx method call, then the port argument of configure_jmx function will not be used
+# when nodetool parses this file and port from cassandra.yaml will be parsed instead,
 # if not found there either, it defaults to 7199.
 #
 # For security reasons, you should not expose this port to the internet.  Firewall it if needed.
diff --git a/tools/bin/fqltool b/tools/bin/fqltool
index dc49e50246..dd4a395615 100755
--- a/tools/bin/fqltool
+++ b/tools/bin/fqltool
@@ -37,17 +37,6 @@ if [ -z "$CASSANDRA_CONF" -o -z "$CLASSPATH" ]; then
     exit 1
 fi
 
-# Run cassandra-env.sh to pick up JMX_PORT
-if [ -f "$CASSANDRA_CONF/cassandra-env.sh" ]; then
-    JVM_OPTS_SAVE=$JVM_OPTS
-    MAX_HEAP_SIZE_SAVE=$MAX_HEAP_SIZE
-    . "$CASSANDRA_CONF/cassandra-env.sh"
-    MAX_HEAP_SIZE=$MAX_HEAP_SIZE_SAVE
-    JVM_OPTS=$JVM_OPTS_SAVE
-fi
-
-# JMX Port passed via cmd line args (-p 9999 / --port 9999 / --port=9999)
-# should override the value from cassandra-env.sh
 ARGS=""
 JVM_ARGS=""
 while true
diff --git a/tools/bin/jmxtool b/tools/bin/jmxtool
index b46305c08f..b2372c2db5 100755
--- a/tools/bin/jmxtool
+++ b/tools/bin/jmxtool
@@ -37,17 +37,6 @@ if [ -z "$CASSANDRA_CONF" -o -z "$CLASSPATH" ]; then
     exit 1
 fi
 
-# Run cassandra-env.sh to pick up JMX_PORT
-if [ -f "$CASSANDRA_CONF/cassandra-env.sh" ]; then
-    JVM_OPTS_SAVE=$JVM_OPTS
-    MAX_HEAP_SIZE_SAVE=$MAX_HEAP_SIZE
-    . "$CASSANDRA_CONF/cassandra-env.sh"
-    MAX_HEAP_SIZE=$MAX_HEAP_SIZE_SAVE
-    JVM_OPTS=$JVM_OPTS_SAVE
-fi
-
-# JMX Port passed via cmd line args (-p 9999 / --port 9999 / --port=9999)
-# should override the value from cassandra-env.sh
 ARGS=""
 JVM_ARGS=""
 while true