JSPM

Parallel Shell

This is a super simple npm module to run shell commands in parallel. All processes will share the same stdout/stderr, and if any command exits with a non-zero exit status, the rest are stopped and the exit code carries through.

Motivation

How is this different than:

$ cmd1 & cmd2 & cmd3

• Cross platform -- works on Unix or Windows.

• & creates a background process, which only exits if you kill it or it ends. parallelshell will autokill processes if one of the others dies.

• command1 & command2 & command3 will wait in the terminal until command3 ends only. parallelshell will wait until all 3 end.

• If command1 or command2 exit with non-zero exit code, then this will not effect the outcome of your shell (i.e. they can fail and npm/bash/whatever will ignore it). parallelshell will not ignore it, and will exit with the first non-zero exit code.

• Pressing Ctrl+C will exit command3 but not 1 or 2. parallelshell will exit all 3

• parallelshell outputs all jobs stdout/err to its stdout/err. background jobs do that... kind of coincidentally (read: unreliably)

Install

Simply run the following to install this to your project:

npm i --save-dev parallelshell

Or, to install it globally, run:

npm i -g parallelshell

Usage

To use the command, simply call it with a set of strings - which correspond to shell arguments, for example:

parallelshell "echo 1" "echo 2" "echo 3"

This will execute the commands echo 1 echo 2 and echo 3 simultaneously.

Note that on Windows, you need to use double-quotes to avoid confusing the argument parser.

Available options:

-h, --help         output usage information
-v, --verbose      verbose logging
-w, --wait         will not close sibling processes on error