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The Linux Kernel Deprecates The 80 Character Line Coding Style

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Linux

The Linux kernel has officially deprecated its coding style that the length of lines of code comply with 80 columns as the "strong preferred limit".

The Linux kernel like many long-standing open-source projects has a coding style guideline that lines of code be 80 columns or less, but now that while still recommended is no longer going to be as enforced.

This stems from Linus Torvalds commenting on Friday that excessive linebreaks are bad and is against ugly wrapped code that is strictly sticking to 80 characters per line. This is part of the broader trend that most are no longer using 80x25 terminals but with today's high resolution displays the terminal sizes are often larger though some preferring the default in order to allow more terminals to be displayed simultaneously on their nice displays.

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Original from Torvalds:

  • clean up kernel_{read,write} & friends v2
    Not necessarily.
    
    Excessive line breaks are BAD. They cause real and every-day problems.
    
    They cause problems for things like "grep" both in the patterns and in
    the output, since grep (and a lot of other very basic unix utilities)
    is fundamentally line-based.
    
    So the fact is, many of us have long long since skipped the whole
    "80-column terminal" model, for the same reason that we have many more
    lines than 25 lines visible at a time.
    
    And honestly, I don't want to see patches that make the kernel reading
    experience worse for me and likely for the vast majority of people,
    based on the argument that some odd people have small terminal
    windows.
    
    If you or Christoph have 80 character lines, you'll get possibly ugly
    wrapped output. Tough. That's _your_ choice. Your hardware limitations
    shouldn't be a pain for the rest of us.
    
    Longer lines are fundamentally useful. My monitor is not only a lot
    wider than it is tall, my fonts are universally narrower than they are
    tall. Long lines are natural.
    
    When I tile my terminal windows on my display, I can have 6 terminals
    visible at one time, and that's because I have them three wide. And I
    could still fit 80% of a fourth one side-by-side.
    
    And guess what? That's with my default "100x50" terminal window (go to
    your gnome terminal settings, you'll find that the 80x25 thing is just
    an initial default that you can change), not with some 80x25 one. And
    that's with a font that has anti-aliasing and isn't some pixelated
    mess.
    
    And most of my terminals actually end up being dragged wider and
    taller than that. I checked, and my main one is 142x76 characters
    right now, because it turns out that wider (and taller) terminals are
    useful not just for source code.
    
    Have you looked at "ps ax" output lately? Or used "top"? Or done "git
    diff --stat" or any number of things where it turns out that 80x25 is
    really really limiting, and is simply NO LONGER RELEVANT to most of
    us.
    
    So no. I do not care about somebody with a 80x25 terminal window
    getting line wrapping.
    
    For exactly the same reason I find it completely irrelevant if
    somebody says that their kernel compile takes 10 hours because they
    are doing kernel development on a Raspberry PI with 4GB of RAM.
    
    People with restrictive hardware shouldn't make it more inconvenient
    for people who have better resources. Yes, we'll accommodate things to
    within reasonable limits. But no, 80-column terminals in 2020 isn't
    "reasonable" any more as far as I'm concerned. People commonly used
    132-column terminals even back in the 80's, for chrissake, don't try
    to make 80 columns some immovable standard.
    
    If you choose to use a 80-column terminal, you can live with the line
    wrapping. It's just that simple.
    
    And longer lines are simply useful. Part of that is that we aren't
    programming in the 80's any more, and our source code is fundamentally
    wider as a result.
    
    Yes, local iteration variables are still called 'i', because more
    context just isn't helpful for some anonymous counter. Being concise
    is still a good thing, and overly verbose names are not inherently
    better.
    
    But still - it's entirely reasonable to have variable names that are
    10-15 characters and it makes the code more legible. Writing things
    out instead of using abbreviations etc.
    
    And yes, we do use wide tabs, because that makes indentation something
    you can visually see in the structure at a glance and on a
    whole-function basis, rather than something you have to try to
    visually "line up" things for or count spaces.
    
    So we have lots of fairly fundamental issues that fairly easily make
    for longer lines in many circumstances.
    
    And yes, we do line breaks at some point. But there really isn't any
    reason to make that point be 80 columns any more.
    
                      Linus
    

Now in Slashdot

  • Linus Torvalds Argues Against 80-Column Line Length Coding Style, As Linux Kernel Deprecates It

    "Yes, staying withing 80 columns is certainly still _preferred_," notes the official commit message for this change. "But it's not the hard limit that the checkpatch warnings imply, and other concerns can most certainly dominate. Increase the default limit to 100 characters. Not because 100 characters is some hard limit either, but that's certainly a 'what are you doing' kind of value and less likely to be about the occasional slightly longer lines.'"

80-characters-per-line limits should be terminal...

  • 80-characters-per-line limits should be terminal, says Linux kernel chief Linus Torvalds

    Linux kernel overlord Linus Torvalds has railed against 80-character-lines as a de facto programming standard and has moved to make reminders to keep things short a thing of the past.

    Torvalds weighed in on a Linux kernel clean-up post that somehow strayed into the topic of line lengths. Some advocated for the retention of 80-character lines on grounds that they're a long-standing convention and that large monitors can handle many small windows when column width is limited.

    Torvalds respectfully disagreed on grounds that limiting lines to 80 characters makes for lots of line breaks.

    "Excessive line breaks are BAD. They cause real and every-day problems," he wrote.

    "They cause problems for things like 'grep' both in the patterns and in the output, since grep (and a lot of other very basic unix utilities) is fundamentally line-based."

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