Replaced os.system() with subprocess.run()

This is some groundwork for #31, since the `subprocess` module might have some capabilities that will help us capture and process the output.

history.py

@@ -1,9 +1,7 @@
 #!/usr/bin/python3
-import os
 from os.path import exists, expanduser
 import sys
-from datetime import datetime
-
+import subprocess
 
 #Fetch LOGPATH into variable "log_path"
 def get_log_path():
@@ -12,20 +10,21 @@ def get_log_path():
     config_location = home_folder + "/.config/workoutPlan.conf"
     stream = open(config_location, "r")
     if exists(config_location):
-      log_path = home_folder + "/" + stream.readline().strip("LOGPATH=~")
+      log_path = home_folder + stream.readline().strip("LOGPATH=~")
       log_path = log_path.strip()
       return log_path
   except FileNotFoundError as e:
     sys.exit("No config file found to determine LOGPATH")
 
 def  display_files(arg1):
-  log_path = (get_log_path())
+  log_path = get_log_path()
   if arg1 == "abc":
     print("Sorting alfabetically")
-    os.system('tree ' + log_path + ' -i --dirsfirst')
+    command = ["tree", log_path, "-i", "--dirsfirst"]
   else:
     print("Sorting by time")
-    os.system('tree ' + log_path + ' -t --timefmt "%a %d-%b" --noreport')
+    command = ["tree", log_path, "-t", "--timefmt", "%a %d-%b", "--noreport"]
+  subprocess.run(command)
 
 if len(sys.argv) == 2:
   display_files(sys.argv[1])