Tag Archives: multiple

parallel: Working along the same lines

I have been messing with parallel all morning, trying to get it to do the same things that I see in the videos, tutorial and examples.

If you’ve not heard of it, parallel should (and by all accounts usually does) split CPU-intensive jobs across processors, which should drastically reduce the time they require to finish.

But I’m not getting much in the way of speed increases, and in some cases it seems to be taking longer.


I’ve tried most combinations I could think of, done them all again as root, even followed examples letter-for-letter from the explanatory videos.

But in almost every case I’m getting much the same performance from functions, so long as they don’t bottleneck at hard drive writes, or something like that.

The coolest thing about parallel — that of course I can’t take advantage of šŸ™„ — is that it can farm out work to other machines.

Yes, that’s what I meant. It can distribute the workload to networked computers and retrieve the results when they all finish.

I think that trumps xargs, which I often see mentioned in the same breath as parallel, because it will take a --max-procs argument and split out to several processors.

But hey, if I could set four computers on the task of compressing my family photos, I’d be all for that.

I’m going to keep tinkering with parallel and if I can get it working in a promising way, I’ll let it make cameos in future posts.

But you’ve got to earn a place on the big screen, friend. :mrgreen:

mmv: Nifty, but takes some getting used to

Mass-rename and mass-move tools are a bit tricky sometimes. I seem to recall having problems even with Windows tools years ago, where Explorer tried to rename all the files I had selected to the same name. That didn’t go over well.

Point being, aside from qmv and the rest of rename-utils, I don’t see many multiple file move tools. mmv is one of the rare ones though.


mmv gives its name to a quadfecta of tools — mmv, plus mcp, mad and mln. You can probably figure out what each one corresponds to, among Unix-ish tools.

mmv is a little cryptic at first, but once you get the hang of it, it works pretty well. The man pages are useful, but more useful for me was this blog post that showed examples. (I’m an assimilator. I follow examples and then break away to do follow my own style.)

To be honest, mmv won’t replace rename-utils for me. I can see where it might be preferable, for simpler, faster moves with quicker patterns and substitutions.

For my money, the real charm of qmv is being able to pipe everything through a text editor, and really get my hands dirty.

Looks like we’re about half way through the M section. There’s hope for me yet. šŸ˜