Re^3: Multiple commands with one system call

[kennethk]

Are you sure about that? When I execute:

perl -e 'system("echo 1;echo 2;echo 3")'

I get the output:

1
2
3

Are you interupting execution, with perhaps ^c? In this case, yes, you are killing all jobs simultaneously. You could execute all three by splitting into multiple system calls:

system ("vp -e $ENV{VREL}");
system ("vscmd set-measure-mode fast; vscmd pg-address-check off");

[renzosilv]

I think when you make the echo call. System calls echo 1 finishes and then calls echo 2. In my case however my first program doesn't finish, I actually have to make the second call while the first one is running. Which is what makes it a bit challenging since the second call will not happen until the first one is done.

[kennethk]

Then at the very least, you need a fork or threads. Depending on some very practical details, I would probably use IPC::Open2 to monitor progress of the child progress so you know when to execute your secondary commands. Some details of interprocess communication are discussed in perlipc.

[shriken]

if Perl detects any shell meta-characters, it forks-and-exec a shell to handle the command. So you can jam a series of shell commands into your system() call. Note that I said "can", not "this is a good idea." ;)