When you enter a command you type its name at the prompt, followed by a space and any parameters for the command. For example, all of these could be valid commands:
copy file1 file2 d:\
"c:\program files\JPSoft\tcmd17\tcc.exe" /LF
The last three commands above include both a command name, and one or more parameters. There are no spaces within the command name (except in quoted file names), but there is a space between the command name and any options or parameters, and there are spaces between the options and parameters.
Some commands may work when options or parameters are entered directly after the command (without an intervening space, e.g. dir/p), or when several options or parameters are entered without spaces between them (e.g. dir /2/p). A very few older programs may even require this approach. However, leaving out spaces this way is usually technically incorrect, and is not recommended as a general practice, as it may not work for all commands.
If the command name includes a path, the elements must be separated with backslashes (e.g. F:\UTIL\MAPMEM). If you are accustomed to Linux syntax where forward slashes are used in command paths, and want TCC to recognize this approach, you can set the Unix/Linux-style Paths option.