Tracking progress with xargs

command-line-interfacexargs

I'm using xargs to execute a command on a set of input parameters something like this:

cat <someinput> | xargs -n 1 -P 5 <somecmd>

The input file is really long and take a long time to run. So I'm just waiting for the command prompt to show up. Is there a way to display a progress bar for the number of input arguments that have completed?

I tried using 'bar' but I always got an 'infinite' throughput. It seems like xargs reads the entire input before executing commands.

http://i.stack.imgur.com/5Wsgx.gif

Best Answer

If you have GNU Parallel you can run:

cat <someinput> | parallel --bar -P 5 <somecmd>

GNU Parallel is a general parallelizer and makes is easy to run jobs in parallel on the same machine or on multiple machines you have ssh access to.

If you have 32 different jobs you want to run on 4 CPUs, a straight forward way to parallelize is to run 8 jobs on each CPU:

Simple scheduling

GNU Parallel instead spawns a new process when one finishes - keeping the CPUs active and thus saving time:

GNU Parallel scheduling

Installation

A personal installation does not require root access. It can be done in 10 seconds by doing this:

(wget -O - pi.dk/3 || curl pi.dk/3/ || fetch -o - http://pi.dk/3) | bash

For other installation options see http://git.savannah.gnu.org/cgit/parallel.git/tree/README

Learn more

See more examples: http://www.gnu.org/software/parallel/man.html

Watch the intro videos: https://www.youtube.com/playlist?list=PL284C9FF2488BC6D1

Walk through the tutorial: http://www.gnu.org/software/parallel/parallel_tutorial.html

Sign up for the email list to get support: https://lists.gnu.org/mailman/listinfo/parallel

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