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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?
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Running Multiple Commands as a Single Job We can start multiple commands as a single job through three steps: Combining the commands – We can use “;“, “&&“, or “||“ to concatenate our commands, depending on the requirement of conditional logic, for example: cmd1; cmd2 && cmd3 || cmd4.
Ampersand Operator (&) Sixth Bash shell command line Chaining Operator (Linux operator) is Ampersand Operator (&). Ampersand Operator is a kind of operator which executes given commands in the background. You can use this operator to execute multiple commands at once.
You can use the & to start multiple background jobs. This will start multiple jobs running in the background. If you want to keep a job running in the background, once you exit the terminal you can use nohup .
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.
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