• seaQueue@lemmy.world
    931·
    6 months ago

    Gentoo users would be really mad about this if they weren’t still building their web browsers and could get online

  • henfredemars@infosec.pubEnglish
    31·
    6 months ago

    Why does this option without specifying a number of threads even exist? It might as well be footgun mode.

    • seaQueue@lemmy.world
      17·
      6 months ago

      I’m pretty sure it’s “run as many threads as there are cores” mode, though if you’re running it in a terminal I always find it best to use nproc-1 or -2 so the machine actually stays usable.

    • Artyom@lemm.ee
      81·
      6 months ago

      I don’t think I’ve ever used -j without specifying as many cores as I have, so it sounds completely reasonable.

    • MajorHavoc@programming.dev
      32·
      6 months ago

      I believe the left hand is a shell fork-bomb, on the assumption that anything that zany is probably malicious.

      And the right hand is a way to tell Make to use up all available system resources:

      "-j [jobs]’ ¶
‘--jobs[=jobs]’
Specifies the number of recipes (jobs) to run simultaneously. With no argument, make runs as many recipes simultaneously as possible. If there is more than one ‘-j’ option, the last one is effective. See Parallel Execution, for more information on how recipes are run. Note that this option is ignored on MS-DOS."

      Edit: I think the make command is technically only a problem when run for a Makefile that tries to do too many things, and has at least one mistake in dependency controls. So… for every Makefile I ever encountered (or that I ever wrote!)

      Yeah. They’re the same picture

      • Voroxpete@sh.itjust.works
        23·
        6 months ago

        You are correct, left hand is a fork bomb. Specifically, it creates and then runs a function named “:”. What this function does is pipe its output into itself while running in a background process, which instantly spawns infinite copies of itself. Technically I believe the : character could be any character as its just a name. The creator just picked a colon for aesthetics.

        • laurelraven@lemmy.blahaj.zone
          10·
          6 months ago

          I always just kind of glazed over looking at that and just know “it’s a fork bomb” and basically what it does

          With your explanation, I can now actually understand all the parts and how they work, it actually makes sense

        • Mixel@feddit.de
          3·
          6 months ago

          Now I get why it does what it does and how it works. I never thought that the colon was the variable name but it makes so much sense!

      • Max-P@lemmy.max-p.me
        5·
        6 months ago

        I think it can also get weird when you call other makefiles, like if you go make -j64 at the top level and that thing goes on to call make on subprojects, that can be a looooot of threads of that -j gets passed down. So even on that 64 core machine, now you have possibly 4096 jobs going, and it surfaces bugs that might not have been a problem when we had 2-4 cores (oh no, make is running 16 jobs at once, the horror).