diff --git a/lib/tdm_reaper.cpp b/lib/tdm_reaper.cpp
index df04a80..86a7d7c 100644
--- a/lib/tdm_reaper.cpp
+++ b/lib/tdm_reaper.cpp
@@ -673,7 +673,7 @@ void tdm_reaper::print_channel(std::string &id, const char* filename, bool inclu
   fou.close();
 }
 
-void tdm_reaper::print_group(std::string &id, const char* filename, bool include_meta)
+void tdm_reaper::print_group(std::string &id, const char* filename, bool include_meta, char sep)
 {
   // check for group id
   if ( this->tdmchannelgroups_.count(id) != 1 )
@@ -759,12 +759,22 @@ void tdm_reaper::print_group(std::string &id, const char* filename, bool include
       {
         if ( allchns.at(chi).size() > row )
         {
-          fou<<std::setw(width)<<std::left<<allchns.at(chi).at(row);
+          // use given csv separator token
+          if ( sep == ' ' )
+          {
+            fou<<std::setw(width)<<std::left<<allchns.at(chi).at(row);
+          }
+          else
+          {
+            fou<<allchns.at(chi).at(row);
+          }
         }
         else
         {
           fou<<std::setw(width)<<std::left<<"";
         }
+
+        if ( chi+1 < chngrp.channels_.size() ) fou<<sep;
       }
       fou<<"\n";
     }
diff --git a/lib/tdm_reaper.hpp b/lib/tdm_reaper.hpp
index 056c7f3..c4ed66d 100644
--- a/lib/tdm_reaper.hpp
+++ b/lib/tdm_reaper.hpp
@@ -216,7 +216,7 @@ public:
 
   // dump a single channel/entire group (identified by id) to file
   void print_channel(std::string &id, const char* filename, bool include_meta = true);
-  void print_group(std::string &id, const char* filename, bool include_meta = true);
+  void print_group(std::string &id, const char* filename, bool include_meta = true, char sep = ' ');
 
 private:
 
diff --git a/src/main.cpp b/src/main.cpp
index 688aeb6..f013d77 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -192,8 +192,16 @@ optkeys parse_args(int argc, char* argv[], bool showargs = false)
       {
         if ( argc > i+1 )
         {
-          prsdkeys.insert(std::pair<std::string,std::string>("csvsep",argv[i+1]));
-          i += 1;
+          if ( std::string(argv[i+1]).size() == 1 )
+          {
+            prsdkeys.insert(std::pair<std::string,std::string>("csvsep",argv[i+1]));
+            i += 1;
+          }
+          else
+          {
+            std::cerr<<"invalid argument of --csvsep\n";
+            prsdkeys.insert(std::pair<std::string,std::string>("invalidoption",argv[i+1]));
+          }
         }
         else
         {
@@ -232,7 +240,7 @@ int main(int argc, char* argv[])
   optkeys cfgopts = parse_args(argc,argv);
 
   // show all CLI arguments
-  if ( false)
+  if ( false )
   {
     for ( optkeys::iterator it=cfgopts.begin(); it!=cfgopts.end(); ++it )
     {
@@ -335,7 +343,7 @@ int main(int argc, char* argv[])
               std::filesystem::path outfile = pd / filenm;
 
               // write entire channelgroup to file
-              jack.print_group(id,outfile.c_str(),includemeta);
+              jack.print_group(id,outfile.c_str(),includemeta,csvsep.at(0));
             }
           }
         }