Executing DOS shell commands via system()

Grygonos has asked for the wisdom of the Perl Monks concerning the following question:

Replies are listed 'Best First'.
Re: Executing DOS shell commands via system() by cbro (Pilgrim) on Jun 06, 2003 at 13:45 UTC
You should use the Perl functions `unlink()` to delete a file and `copy() (From the File::Copy module)` to copy a file.	[reply] [d/l] [select]
Re: Re: Executing DOS shell commands via system() by Grygonos (Chaplain) on Jun 06, 2003 at 13:52 UTC
wow... showing the inexperience huh... hehe thanks :)	[reply]
Re: Re: Re: Executing DOS shell commands via system() by cbro (Pilgrim) on Jun 06, 2003 at 14:09 UTC
And so appeared, perlmonks, to help us all out. Everybody is inexperienced at some subset of every language.	[reply]
Re: Executing DOS shell commands via system() by crouchingpenguin (Priest) on Jun 06, 2003 at 14:13 UTC
cbro was spot on. Also, concerning your use of system... This is probably what you want/mean: `system(@args) == 0 \|\| die "Failed to delete: $!";` See system concerning return value. cp ---- "Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic."	[reply] [d/l]
Re: Executing DOS shell commands via system() by Jenda (Abbot) on Jun 06, 2003 at 14:49 UTC
If you are using the `system( @args)` style you should NOT include any spaces at the end of the command name or parameters. If the `erase` is a command implemented within cmd.exe all you have to do is to call the cmd.exe: `@args = ('cmd.exe', '/c', 'erase', $filename);` [download] Of course in this case `unlink($filename)` would be better. Jenda Always code as if the guy who ends up maintaining your code will be a violent psychopath who knows where you live. -- Rick Osborne Edit by castaway: Closed small tag in signature	[reply] [d/l] [select]
Re^2: Executing DOS shell commands via system() (/c nits) by tye (Sage) on Jun 06, 2003 at 20:37 UTC
`@args = ('cmd.exe', '/c', 'erase', $filename);` [download] If Win32 had "real"™ command-line argument processing, then that wouldn't work. For example, in Unix you have to use: `@args = ( 'sh', '-c', "erase $filename" );` [download] and this is important in case you want to quote arguments to be given to the internal command. But going very far down that road gets rather complicated quickly so I'll leave that for another time. The reason your code works is because, in Win32, `system(@args)` is (quite unfortunately) exactly the same as `system("@args")` because Win32 only deals with command lines while Unix (and C) want to deal with lists of command arguments. This can make getting the proper arguments passed in quite difficult, especially since it also means that each program parses its own command line and so you often have to prepare/quote your arguments different for different commands. Also note that Perl will do the "cmd /c" trick for you automatically (if it can't find a "erase.*" executable in your PATH). - tye	[reply] [d/l] [select]
Re: Executing DOS shell commands via system() (done) by tye (Sage) on Jun 06, 2003 at 20:22 UTC
FYI, Perl already does that for you! `C:\>set prom PROMPT=$P$G C:\>perl -e "system('set prom')" PROMPT=$P$G C:\>perl -e "system('set.exe prom')" Environment variable .exe not defined` [download] That last example is in there to show you that is isn't running some SET.EXE but is really running cmd.exe and passing it the command "set prom". - tye	[reply] [d/l]


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