Assorted less(1) tips — HN Discussion

Full HN thread discussing Tim Chase's blog post on less(1) tips.

Selected Comments

teeray: less +F starts less following stdin or file. <C-c> breaks following; F resumes. Better than tail in many circumstances.

CBLT: When following a pipe (kubectl logs | less +F), <C-c> is sent to all processes in the pipeline, killing the source. Less provides <C-x> to stop following, but most shells intercept it.

mananaysiempre: The shell isn't active while less is running. Terminal job control (^Z → SIGTSTP) is a kernel function, not shell-level input processing. Configurable via stty susp/stty intr/stty quit.

fuzztester: Requested tutorial-style book recommendations on Unix system programming beyond man pages and Kerrisk's TLPI.

joombaga: With tail you can press enter to add visual separators between log groups. The only reason they still use tail over less for following.

xg15: "Follow" is just "keep polling after EOF" — no sophisticated file descriptor trickery. Software can switch modes on the fly.

layer8: Wanted a mode that follows new output while letting you navigate around, with an autoscroll toggle.

gerdesj / tstack: Recommended lnav — always polls files for new data, auto-scrolls when at end, sticks to position otherwise, highlights search matches in new data.

JayGuerette: -X or --no-init prevents clearing the screen. Useful for copy/paste from content to command line.

Izkata: Combines with -E (quit immediately if output smaller than terminal). Their go-to: less -SEXIER. Specifying E twice doesn't do anything except make it easier to remember.

jlokier: Recommends -FX over -EX. Both quit if output smaller than screen, but -FX doesn't quit if output larger and you jump to end. git uses LESS=FRX less by default.

kccqzy: Hates -E — quitting immediately breaks muscle memory. The q key becomes input to the shell prompt. Values consistency over saving a keystroke.

etra0: Uses & to filter (show matching) and &! to filter-out (hide matching). Both support regex. A bit slow sometimes but saves on removing noise from logfiles.

inejge: -L skips preprocessing — prevents rotated log files (logfile.1, logfile.2) from being treated as man page source and piped through nroff. Also: Ctrl-R as first character of a search string does literal search, not regex.

ilyagr: Shows how to bind ^q to quit without clearing screen (like less -X), while q clears screen. Uses ~/.config/lesskey. The option is --redraw-on-quit, which is slightly better than -X in every way on newer less versions.

jez: Binds s to back-scroll in ~/.lesskey so d and s are adjacent for one-handed page up/down. Notes macOS's default less doesn't support lesskey — install via Homebrew.

Redisclever: Uses ma (mark), navigation, then |a to pipe region to external command (e.g., cat >somefile). Great for saving snippets. Also -j setting for search context positioning.

obezyian: Uses less piping for interactive git-log: detects when git-log is running via bash debug trap + terminal title + keyd, sets up shortcuts to pipe the top-line commit hash to scripts for git-show or fixup.

alkh: Recommends lesspipe for syntax highlighting and file rendering (pdf, markdown) in less. Typically disabled in pipes so scripts behave as intended.

somat: OpenBSD man provides tags to the pager (:t test in man ksh). Neat but never used — the simple uniform interface of / search wins over sophisticated navigation, similar to how man pages beat info pages.

GuB-42: The ! command is a privilege escalation vector — if a script running as root uses less, !bash gives a root shell.

jmholla: Set LESSSECURE=1 to disable external commands. Most distros don't ship with restricted less by default.

btdmaster / osmsucks: Press s to save data from a pipe to a file — no need to copy/paste or tee ahead of time.

fragmede: Mentions most as alternative pager and glow for rendering markdown in terminal.

linhns: Recommends ov as a modern alternative: https://github.com/noborus/ov

kseistrup: Recommends moor (née moar): https://github.com/walles/moor

_delirium: Jokes about the blog post's claim of "more less tips than the Bible's got Psalms" — there are at least 150 Psalms.

jemfinch: Biggest problem with less: the regex engine is unreasonably slow on large files. Frequently pipes through grep/ripgrep with large -A/-B buffers first.

nvader: Wanted an emacs-lite alternative to less. Self-answered: emacs -nw -e "(view-mode)".

jsrcout: Used less + PCRE for detailed code analysis for years. Bookmarks were a key microtool.

anthk: "If you want security, unset LESSOPEN."