Question

I’m trying to run some commands in paralel, in background, using bash. Here’s what I’m trying to do:

forloop {   //this part is actually written in perl   //call command sequence   print `touch .file1.lock; cp bigfile1 /destination; rm .file1.lock;`; } 

The part between backticks (“) spawns a new shell and executes the commands in succession. The thing is, control to the original program returns only after the last command has been executed. I would like to execute the whole statement in background (I’m not expecting any output/return values) and I would like the loop to continue running.

The calling program (the one that has the loop) would not end until all the spawned shells finish.

I could use threads in perl to spawn different threads which call different shells, but it seems an overkill…

Can I start a shell, give it a set of commands and tell it to go to the background?

Answer 1

I haven’t tested this but how about

print `(touch .file1.lock; cp bigfile1 /destination; rm .file1.lock;) &`; 

The parentheses mean execute in a subshell but that shouldn’t hurt.