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.
Maybe OT, but I thought for a long time that "follow" was some sophisticated file descriptor trickery that required you to somehow "stream" the file while reading and would therefore be incompatible with opening a file "normally".
My mind was blown when finding out its really just "keep on polling after EOF". Meaning there is absolutely no difference between opening a file normally and "following" a file - and software could easily switch between the two "modes" on the fly.
With `tail` you can press enter a few times to put some empty lines after the last line. This is useful e.g. when you trigger a function multiple times and want to easily see line groups from each attempt. It's the only reason I still use `tail` for following when `less` is available.
A visual mark would be nice, agreed. I haven't tried it, but I wonder if you could approximate it with the bookmarking feature that less(1) does have. It wouldn't be visible, but it would scroll to a consistent mark.
If you're following a pipe (such as `kubectl logs | less +F`), <C-c> is sent to all processes in a pipeline, so it stops less from following and it stops the other process entirely. Then you can't start following again with F, or load more data in with G.
Less provides an alternative of <C-x> to stop following, but that is intercepted by most shells.
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.
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.
I recommend -FX instead of -EX. They both quit immediately if the output is smaller than the screen size, but -FX does not quit if the output is larger and you jump to the end of a large file, so you can continue to do things like scroll back or search.
git uses "less -FRX" by default. This is how I learned about -F.
(To be pedentic, git uses "LESS=FRX less", which accomplishes the same thing.)
I hate -E. Quitting immediately does not do good things to my muscle memory. I’m using to hitting q to quit less when I am done. Now the q key becomes part of the input to the shell prompt (or worse if there’s a different tool invoking less and now q might be interpreted differently by that tool). I value the consistency of user interaction more than saving a keystroke.
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 :).
-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.)
If a script running as root uses less (or vi), just do "!bash" and you have a root shell. Note that systems that let you do this are usually pretty weak, and there are often many other ways to get root access, but this is a particularly simple one that I used a few times in the past.
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]
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.
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.
My mind was blown when finding out its really just "keep on polling after EOF". Meaning there is absolutely no difference between opening a file normally and "following" a file - and software could easily switch between the two "modes" on the fly.
Less provides an alternative of <C-x> to stop following, but that is intercepted by most shells.
" ... 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.
...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.
git uses "less -FRX" by default. This is how I learned about -F.
(To be pedentic, git uses "LESS=FRX less", which accomplishes the same thing.)
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.
-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.)
But there are (at least) 150 Psalms! You're going to need more less tips to match that.
Also useful for privilege escalation...
If a script running as root uses less (or vi), just do "!bash" and you have a root shell. Note that systems that let you do this are usually pretty weak, and there are often many other ways to get root access, but this is a particularly simple one that I used a few times in the past.
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...
https://github.com/charmbracelet/glow/compare/master...fragm...