Assorted less(1) tips

(blog.thechases.com)

76 points | by todsacerdoti 4 hours ago

10 comments

  • teeray 2 hours ago
    Surprised they missed follow! It’s a bit odd to use, but once you get used to it it’s better than tail in many circumstances IMO. `less +F` starts less following stdin or whatever file argument you’ve provided. <C-c> breaks following, allowing you to search around a business-as-usual `less` session. Hitting `F` (that’s uppercase) starts following again. Yes, you can just start following within a session with `F` too if you forgot to add +F to the `less` invocation.
    • layer8 1 hour ago
      It would be nice to have a mode that follows in the sense of automatically picking up new output, but that simultaneously would let you navigate around, similar to how terminals behave. Then you’d only need an autoscroll toggle for when you’re at the bottom.
    • sprt 2 hours ago
      I'm so mad that I didn't know the hitting F thing!
  • JayGuerette 2 hours ago
    Also -X or --no-init

    " ... desirable if the deinitialization string does something unnecessary, like clearing the screen."

    I prefer to not clear the screen. I usually want to continue to refer to something or even copy/paste from the content to my current command line.

    • Izkata 1 hour ago
      And combined with -E, it'll quit immediately if the output is smaller than the terminal size.

      ...And combined with some of the other options in the post, my go-to has been "less -SEXIER" for a long time. Specifying E twice doesn't seem to do anything except make this easier to remember.

      • marcosdumay 20 minutes ago
        I'm reading it correctly that it will cause less to exit if you scroll until the end of file even if the file is larger than the terminal size?
        • Izkata 14 minutes ago
          Yeah; in both cases (text is larger or smaller than terminal) it makes "less" act the same as "more" with auto-exiting.
  • etra0 2 hours ago
    The tip that I've been using quite a lot lately by debugging long log files is using `&` to filter what I want to read and `&!` to filter-out what's not useful (and they support regexes).

    Admittedly, they are a bit slow sometime and sure, you could use `grep -v` then pipe which is way faster, but they've saved me on removing noise from logfiles from time to time when you don't always know what to filter beforehand :).

    EDIT: It was in TFA.

  • jez 1 hour ago
    Less can be configured with a ~/.lesskey file

    I have a single line in my config[1] which binds s to back-scroll, so that d and s are right next to each other and I can quickly page up/down with one hand.

    If you’re on macOS, you may not be able to use this unless you install less from Homebrew, or otherwise replace the default less.[2]

    [1] https://github.com/jez/dotfiles/blob/master/lesskey#L2

    [2] https://apple.stackexchange.com/questions/27269/is-less1-mis...

  • inejge 1 hour ago
    Two things that have helped me a lot of times:

    -L: skip preprocessing the input file. When opening rotated log files with the names like logfile.1, logfile.2... the default preprocessor on some distros will recognize them as man page source and helpfully pipe through nroff. If the file is largish this introduces an annoying pause. Using -L skips all that.

    Ctrl-R as the first character of a search string will search for that literal string, not the regular expression. Nice if you have regex metacharacters in the search string and don't want to bother with escaping (and don't need the regex facilities, of course.)

  • linhns 1 hour ago
    I like less and found that https://github.com/noborus/ov can be a good modern alternative to it.
    • eitau_1 30 minutes ago
      Looks cool! Annoyingly less sometimes bugs out and starts spinning, have to kill it from the outside.
  • btdmaster 2 hours ago
    You can also press `s` to save data from a pipe to a file rather than manually copy pasting.
  • eulgro 2 hours ago
    Some of these come intuitively when you know how to use vim. I expect to be able to search when pressing / in terminal programs, just like I expect Ctrl+F to work in GUIs.
  • fragmede 2 hours ago
    There -R to quit if the file is less than the screen size. There's also most as an alternative pager, and also glow (of course which, my fork of it is better) to render md files in the terminal.
  • pvtmert 48 minutes ago
    s/assorted/useful/