diff --git a/src/commands/monorepo/set-if-file-changed.yml b/src/commands/monorepo/set-if-file-changed.yml
index 914fbdb6..503726d0 100644
--- a/src/commands/monorepo/set-if-file-changed.yml
+++ b/src/commands/monorepo/set-if-file-changed.yml
@@ -1,7 +1,7 @@
 description: |
   Set the given env var to true if a changed file matches one of the given patterns.
-  The `CHANGED_FILES` environment variable must be set with the `get_changes_files` command prior
-  to running this command.
+  The `CHANGED_FILES_FILE` environment variable (a path to the changed-files list, set by the
+  `get_changed_files` command) must be set prior to running this command.
 parameters:
   file-patterns:
     description: |
@@ -22,7 +22,7 @@ steps:
 
         << parameters.target-env-var >>=false
         for FILE_PATTERN in ${FILE_PATTERNS?}; do
-          if egrep "^.\s+$FILE_PATTERN\$" \<<< "$CHANGED_FILES"; then
+          if egrep "^.\s+$FILE_PATTERN\$" "${CHANGED_FILES_FILE:?}"; then
             << parameters.target-env-var >>=true
             echo "Found $FILE_PATTERN in changed files, setting << parameters.target-env-var >> to true"
             break
diff --git a/src/commands/monorepo/set-service-data-json.yml b/src/commands/monorepo/set-service-data-json.yml
index c855abb2..290d5529 100644
--- a/src/commands/monorepo/set-service-data-json.yml
+++ b/src/commands/monorepo/set-service-data-json.yml
@@ -1,7 +1,7 @@
 description: |
   Set the service metadata array in a json file.
-  The `CHANGED_FILES` environment variable must be set with the `get_changes_files` command prior
-  to running this command.
+  The `CHANGED_FILES_FILE` environment variable (a path to the changed-files list, set by the
+  `get_changed_files` command) must be set prior to running this command.
 parameters:
   service-directories:
     description: |
@@ -36,7 +36,7 @@ steps:
 
             echo "Checking if $SERVICE was modified..."
             MODIFIED=false
-            if grep "$DIRECTORY/$SERVICE" \<<< "${CHANGED_FILES?}"; then
+            if grep "$DIRECTORY/$SERVICE" "${CHANGED_FILES_FILE:?}"; then
               MODIFIED=true
             fi
             COMPONENT_NAME=$(jq --raw-output ".serviceName" $DIRECTORY/$SERVICE/package.json)
diff --git a/src/commands/utils/get_changed_files.yml b/src/commands/utils/get_changed_files.yml
index 4752e2c4..7a380824 100644
--- a/src/commands/utils/get_changed_files.yml
+++ b/src/commands/utils/get_changed_files.yml
@@ -1,11 +1,11 @@
 parameters:
-  target_env_var:
-    description: Environment variable to set with the list of changed files
-    type: env_var_name
-    default: CHANGED_FILES
+  target_file:
+    description: Absolute path to write the list of changed files to. Absolute so it survives consumers that set a custom working_directory (e.g. helm).
+    type: string
+    default: /tmp/changed_files.txt
 steps:
   - run:
-      name: Put list of changed files in << parameters.target_env_var >> environment variable
+      name: Write list of changed files to << parameters.target_file >>
       command: |
        if [[ -z $COMPUTED_BASE_REVISION  ]]; then
           BASE_REVISION="master"
@@ -19,5 +19,5 @@ steps:
        if [[ $BASE == $CIRCLE_SHA1 ]]; then
           BASE="$(git rev-parse HEAD~1)"
        fi
-       FILE_CHANGES="$(git diff --name-status --no-commit-id -r $BASE...$CIRCLE_SHA1)"
-       echo "export << parameters.target_env_var >>=\"$FILE_CHANGES\"" >> "$BASH_ENV"
+       git diff --name-status --no-commit-id -r $BASE...$CIRCLE_SHA1 > "<< parameters.target_file >>"
+       echo "export CHANGED_FILES_FILE=\"<< parameters.target_file >>\"" >> "$BASH_ENV"
diff --git a/src/scripts/helm/get_modified_charts.sh b/src/scripts/helm/get_modified_charts.sh
index 6d1fec86..8bfe0ad2 100644
--- a/src/scripts/helm/get_modified_charts.sh
+++ b/src/scripts/helm/get_modified_charts.sh
@@ -1,7 +1,7 @@
 #!/bin/bash
 
 # Expected environment variables:
-echo "CHANGED_FILES: ${CHANGED_FILES?}"
+echo "CHANGED_FILES_FILE: ${CHANGED_FILES_FILE:?}"
 echo "CHART_DIR: ${CHART_DIR:?}"
 echo "MODIFIED_CHARTS_ENV: ${MODIFIED_CHARTS_ENV:?}"
 
@@ -26,7 +26,7 @@ done
 # Extract only modified charts
 MODIFIED_CHARTS=()
 for CHART in "${ALL_CHARTS[@]}"; do
-    if grep -q -oP "(M|A)\s*${CHART_DIR}${CHART}/${CHART}/.*" <<< "${CHANGED_FILES?}"; then
+    if grep -q -oP "(M|A)\s*${CHART_DIR}${CHART}/${CHART}/.*" "${CHANGED_FILES_FILE:?}"; then
     MODIFIED_CHARTS+=("$CHART")
     fi;
 done
@@ -34,4 +34,4 @@ done
 echo "${MODIFIED_CHARTS[@]}"
 
 # shellcheck disable=SC2145
-echo "export ${MODIFIED_CHARTS_ENV:?}=\"${MODIFIED_CHARTS[@]}\"" >> "$BASH_ENV"
\ No newline at end of file
+echo "export ${MODIFIED_CHARTS_ENV:?}=\"${MODIFIED_CHARTS[@]}\"" >> "$BASH_ENV"