diff --git a/terraform_docs.sh b/terraform_docs.sh
index fba5730fd..964bbcdd0 100755
--- a/terraform_docs.sh
+++ b/terraform_docs.sh
@@ -15,7 +15,7 @@ for file_with_path in "$@"; do
     tfvars_files+=("$file_with_path")
   fi
 
-  let "index+=1"
+  ((index+=1))
 done
 
 readonly tmp_file="tmp_$(date | md5).txt"
@@ -33,11 +33,11 @@ for path_uniq in $(echo "${paths[*]}" | tr ' ' '\n' | sort -u); do
 
   terraform-docs md ./ > "$tmp_file"
 
-  # Replace content between markers with the placeholder - http://fahdshariff.blogspot.no/2012/12/sed-mutli-line-replacement-between-two.html
-  sed -i -n '/BEGINNING OF PRE-COMMIT-TERRAFORM DOCS HOOK/{p;:a;N;/END OF PRE-COMMIT-TERRAFORM DOCS HOOK/!ba;s/.*\n/I_WANT_TO_BE_REPLACED\n/};p' "$text_file"
+  # Replace content between markers with the placeholder - https://stackoverflow.com/questions/1212799/how-do-i-extract-lines-between-two-line-delimiters-in-perl#1212834
+  perl -i -ne 'if (/BEGINNING OF PRE-COMMIT-TERRAFORM DOCS HOOK/../END OF PRE-COMMIT-TERRAFORM DOCS HOOK/) { print $_ if /BEGINNING OF PRE-COMMIT-TERRAFORM DOCS HOOK/; print "I_WANT_TO_BE_REPLACED\n$_" if /END OF PRE-COMMIT-TERRAFORM DOCS HOOK/;} else { print $_ }' "$text_file"
 
-  # Replace placeholder with the content of the file - https://stackoverflow.com/a/31057013/550451
-  sed -i -e "/I_WANT_TO_BE_REPLACED/r $tmp_file" -e "//d" "$text_file"
+  # Replace placeholder with the content of the file
+  perl -i -e 'open(F, "'"$tmp_file"'"); $f = join "", <F>; while(<>){if (/I_WANT_TO_BE_REPLACED/) {print $f} else {print $_};}' "$text_file"
 
   rm -f "$tmp_file"