[fpc-pascal]building a command string

[Nikolay Nikolov]

DONALD PEDDER wrote:

>   Below is the current state of my code. I am getting "invalid TSS" at
>the point I have noted. I don't even know what a "TSS" is! I guess it's
>something to do with strings (I haven't used strings much before either -
>something else lacking in my previous compilers). I searched the doco, but
>couldn't find what I was looking for.
>
TSS has nothing to do with strings. TSS = Task Segment Selector. It's a 
structure used by the intel cpus in protected mode. The message "invalid 
TSS" is probably printed by the DPMI host. (usually cwsdpmi.exe, if you 
are using plain DOS and not a Windows DOS box.) Probably means that you 
messed things up in memory, which can happen quite often when using 
pointers and C-style "strings", etc...

>Exec(GetEnv('COMSPEC'),'/c dir test*');
>tempstr1:='/c copy';
>tempstr2:=' ';
>tempstr:=strcat(tempstr1,tempstr2);
>writeln(tempstr,'*');
>tempstr1:=tempstr;
>tempstr2:=argv[1];
>tempstr:=strcat(tempstr1,tempstr2);
>writeln(tempstr,'*');
>tempstr1:=tempstr;                         < program
>tempstr2:=' ';                             < crashes
>tempstr:=strcat(tempstr1,tempstr2);        < here
>writeln(tempstr,'*');
>tempstr1:=tempstr;
>tempstr2:=argv[1];
>tempstr:=strcat(tempstr1,tempstr2);
>writeln(tempstr,'*');
>tempstr1:=tempstr;
>tempstr2:='.bak /v';
>tempstr:=strcat(tempstr1,tempstr2);
>writeln(tempstr,'*');
>Exec(GetEnv('COMSPEC'),tempstr);
>Exec(GetEnv('COMSPEC'),'/c dir test*');
>
How about 1 line of code :-)
Exec(GetEnv('COMSPEC'), '/c copy '+ParamStr(1)+' '+ParamStr(1)+'.bak /v');

There's no need to even use Pascal for this kind of thing. You could use 
a .bat file:
copy %1 %1.bak /v