Currently Geany, unlike other editors, is using double colons (::) as comment_single. What is the reason? REM (with trailing space) is much more appropriate. A citation: " REM is the standards-compliant, documented statement to insert comments in batch files; double colons are a non-documented and non-compliant way to insert comments". I will give two examples when using "::" is problematic. First example: IF 1 equ 1 ( :: Comment line 1 ECHO Do something REM Comment line 2 :: Comment line 2 ) Here double colons give an error: ") was unexpected at this time." Second example: "C:\Program Files (x86)\WinSCP\WinSCP.com" ^ :: /log="%log_file%" ^   /command ^     "open %serverURL% -hostkey=* -privatekey=%keys%%ppk% -rawsettings TryAgent=0 AuthKI=0" ^     "put  ""%file_send%""" ^     "exit" Because line continuation "^" is applicable to empty label (::), double colons here are commenting out all lines starting from the second to the very end, instead of commenting out only a single line. I believe comment_single should be "comment_single=REM "