diff --git a/message-rich-text.sh b/message-rich-text.sh
old mode 100755
new mode 100644
index ee441fe..410391f
--- a/message-rich-text.sh
+++ b/message-rich-text.sh
@@ -21,7 +21,7 @@
 curl -X POST "https://businessmessages.googleapis.com/v1/conversations/__CONVERSATION_ID__/messages" \
 -H "Content-Type: application/json" \
 -H "User-Agent: curl/business-messages" \
--H "`oauth2l header --json ./service_account_key.json businessmessages`" \
+-H "$(oauth2l header --json ./service_account_key.json businessmessages)" \
 -d "{
   'messageId': '$(uuidgen)',
   'fallback': 'Hello, check out this link https://www.google.com.',
diff --git a/message-text.sh b/message-text.sh
old mode 100755
new mode 100644
index 0f4ca30..0e092d2
--- a/message-text.sh
+++ b/message-text.sh
@@ -21,7 +21,7 @@
 curl -X POST "https://businessmessages.googleapis.com/v1/conversations/__CONVERSATION_ID__/messages" \
 -H "Content-Type: application/json" \
 -H "User-Agent: curl/business-messages" \
--H "`oauth2l header --json ./service_account_key.json businessmessages`" \
+-H "$(oauth2l header --json ./service_account_key.json businessmessages)" \
 -d "{
   'messageId': '$(uuidgen)',
   'text': 'Hello world!',
diff --git a/send-event-representative-joined.sh b/send-event-representative-joined.sh
old mode 100755
new mode 100644
index 47697a5..1e1672f
--- a/send-event-representative-joined.sh
+++ b/send-event-representative-joined.sh
@@ -21,7 +21,7 @@
 curl -X POST "https://businessmessages.googleapis.com/v1/conversations/__CONVERSATION_ID__/events?eventId=6a0af2c6-787d-4097-870d-93fe20351747" \
 -H "Content-Type: application/json" \
 -H "User-Agent: curl/business-messages" \
--H "`oauth2l header --json ./service_account_key.json businessmessages`" \
+-H "$(oauth2l header --json ./service_account_key.json businessmessages)" \
 -d "{
   'eventType': 'REPRESENTATIVE_JOINED',
   'representative': {
diff --git a/send-event-typing-started.sh b/send-event-typing-started.sh
old mode 100755
new mode 100644
index dc8b3d8..b45e48c
--- a/send-event-typing-started.sh
+++ b/send-event-typing-started.sh
@@ -21,7 +21,7 @@
 curl -X POST "https://businessmessages.googleapis.com/v1/conversations/__CONVERSATION_ID__/events?eventId=6a0af2c6-787d-4097-870d-93fe20351747" \
 -H "Content-Type: application/json" \
 -H "User-Agent: curl/business-messages" \
--H "`oauth2l header --json ./service_account_key.json businessmessages`" \
+-H "$(oauth2l header --json ./service_account_key.json businessmessages)" \
 -d "{
   'eventType': 'TYPING_STARTED',
   'representative': {
diff --git a/send-message-authentication-request-suggestion.sh b/send-message-authentication-request-suggestion.sh
old mode 100755
new mode 100644
index dccb9b1..6ee3419
--- a/send-message-authentication-request-suggestion.sh
+++ b/send-message-authentication-request-suggestion.sh
@@ -25,7 +25,7 @@
 curl -X POST "https://businessmessages.googleapis.com/v1/conversations/__CONVERSATION_ID__/messages" \
 -H "Content-Type: application/json" \
 -H "User-Agent: curl/business-messages" \
--H "`oauth2l header --json ./service_account_key.json businessmessages`" \
+-H "$(oauth2l header --json ./service_account_key.json businessmessages)" \
 -d "{
     'messageId': '$(uuidgen)',
     'text': 'Sign in to continue the conversation.',
diff --git a/send-message-fallback.sh b/send-message-fallback.sh
old mode 100755
new mode 100644
index 343f56b..1bd9794
--- a/send-message-fallback.sh
+++ b/send-message-fallback.sh
@@ -22,7 +22,7 @@ curl -X POST \
 "https://businessmessages.googleapis.com/v1/conversations/__CONVERSATION_ID__/messages?forceFallback=true" \
 -H "Content-Type: application/json" \
 -H "User-Agent: curl/business-messages" \
--H "`oauth2l header --json ./service_account_key.json businessmessages`" \
+-H "$(oauth2l header --json ./service_account_key.json businessmessages)" \
 -d "{
     'messageId': '$(uuidgen)',
     'text': 'Hello world!',
diff --git a/send-message-image.sh b/send-message-image.sh
old mode 100755
new mode 100644
index 7ea5aa2..664f26b
--- a/send-message-image.sh
+++ b/send-message-image.sh
@@ -21,7 +21,7 @@
 curl -X POST "https://businessmessages.googleapis.com/v1/conversations/__CONVERSATION_ID__/messages" \
 -H "Content-Type: application/json" \
 -H "User-Agent: curl/business-messages" \
--H "`oauth2l header --json ./service_account_key.json businessmessages`" \
+-H "$(oauth2l header --json ./service_account_key.json businessmessages)" \
 -d "{
     'messageId': '$(uuidgen)',
     'representative': {
diff --git a/send-message-live-agent-request-suggestion.sh b/send-message-live-agent-request-suggestion.sh
old mode 100755
new mode 100644
index eb7a23b..aa9cf7f
--- a/send-message-live-agent-request-suggestion.sh
+++ b/send-message-live-agent-request-suggestion.sh
@@ -22,7 +22,7 @@
 curl -X POST "https://businessmessages.googleapis.com/v1/conversations/__CONVERSATION_ID__/messages" \
 -H "Content-Type: application/json" \
 -H "User-Agent: curl/business-messages" \
--H "`oauth2l header --json ./service_account_key.json businessmessages`" \
+-H "$(oauth2l header --json ./service_account_key.json businessmessages)" \
 -d "{
     'messageId': '$(uuidgen)',
     'text': 'Would you like to chat with a live agent?',
diff --git a/send-message-rich-card-carousel.sh b/send-message-rich-card-carousel.sh
old mode 100755
new mode 100644
index 5b76cb2..ac60332
--- a/send-message-rich-card-carousel.sh
+++ b/send-message-rich-card-carousel.sh
@@ -21,7 +21,7 @@
 curl -X POST "https://businessmessages.googleapis.com/v1/conversations/__CONVERSATION_ID__/messages" \
 -H "Content-Type: application/json" \
 -H "User-Agent: curl/business-messages" \
--H "`oauth2l header --json ./service_account_key.json businessmessages`" \
+-H "$(oauth2l header --json ./service_account_key.json businessmessages)" \
 -d "{
     'messageId': '$(uuidgen)',
     'representative': {
diff --git a/send-message-rich-card.sh b/send-message-rich-card.sh
old mode 100755
new mode 100644
index cfcfae1..089d12c
--- a/send-message-rich-card.sh
+++ b/send-message-rich-card.sh
@@ -21,7 +21,7 @@
 curl -X POST "https://businessmessages.googleapis.com/v1/conversations/__CONVERSATION_ID__/messages" \
 -H "Content-Type: application/json" \
 -H "User-Agent: curl/business-messages" \
--H "`oauth2l header --json ./service_account_key.json businessmessages`" \
+-H "$(oauth2l header --json ./service_account_key.json businessmessages)" \
 -d "{
     'messageId': '$(uuidgen)',
     'representative': {
diff --git a/send-message-suggested-action-dial.sh b/send-message-suggested-action-dial.sh
old mode 100755
new mode 100644
index 22b834e..1781ab2
--- a/send-message-suggested-action-dial.sh
+++ b/send-message-suggested-action-dial.sh
@@ -22,7 +22,7 @@
 curl -X POST "https://businessmessages.googleapis.com/v1/conversations/__CONVERSATION_ID__/messages" \
 -H "Content-Type: application/json" \
 -H "User-Agent: curl/business-messages" \
--H "`oauth2l header --json ./service_account_key.json businessmessages`" \
+-H "$(oauth2l header --json ./service_account_key.json businessmessages)" \
 -d "{
     'messageId': '$(uuidgen)',
     'text': 'Contact support for help with this issue.',
diff --git a/send-message-suggested-action-open-url.sh b/send-message-suggested-action-open-url.sh
old mode 100755
new mode 100644
index 9fe2319..b967868
--- a/send-message-suggested-action-open-url.sh
+++ b/send-message-suggested-action-open-url.sh
@@ -22,7 +22,7 @@
 curl -X POST "https://businessmessages.googleapis.com/v1/conversations/__CONVERSATION_ID__/messages" \
 -H "Content-Type: application/json" \
 -H "User-Agent: curl/business-messages" \
--H "`oauth2l header --json ./service_account_key.json businessmessages`" \
+-H "$(oauth2l header --json ./service_account_key.json businessmessages)" \
 -d "{
     'messageId': '$(uuidgen)',
     'text': 'Hello world!',
diff --git a/send-message-suggested-replies.sh b/send-message-suggested-replies.sh
old mode 100755
new mode 100644
index 80e2c71..398b0ed
--- a/send-message-suggested-replies.sh
+++ b/send-message-suggested-replies.sh
@@ -21,7 +21,7 @@
 curl -X POST "https://businessmessages.googleapis.com/v1/conversations/__CONVERSATION_ID__/messages" \
 -H "Content-Type: application/json" \
 -H "User-Agent: curl/business-messages" \
--H "`oauth2l header --json ./service_account_key.json businessmessages`" \
+-H "$(oauth2l header --json ./service_account_key.json businessmessages)" \
 -d "{
     'messageId': '$(uuidgen)',
     'text': 'Hello, world!',
diff --git a/send-survey.sh b/send-survey.sh
old mode 100755
new mode 100644
index b031ee3..22f85e3
--- a/send-survey.sh
+++ b/send-survey.sh
@@ -21,4 +21,4 @@
 curl -X POST "https://businessmessages.googleapis.com/v1/conversations/__CONVERSATION_ID__/surveys?surveyId=f4bd7576-6c2e-4674-9db4-d697166f63ce" \
 -H "Content-Type: application/json" \
 -H "User-Agent: curl/business-messages" \
--H "`oauth2l header --json ./service_account_key.json businessmessages`" \
\ No newline at end of file
+-H "$(oauth2l header --json ./service_account_key.json businessmessages)"
\ No newline at end of file