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I recommend using `less <FILE>` <shift-F> rather than plain `tail -f <FILE>` because you can ctrl-c to stop the tailing and then search the text using /. You ca

I recommend using `less <FILE>` <shift-F> rather than plain `tail -f <FILE>` because you can ctrl-c to stop the tailing and then search the text using /. You can then resume tailing again later with another <shift-F>.

anyfoo 5y ago
I love to press enter a few times to add a few empty lines to serve as a marker. Plus, I set my terminal scrollback buffer to 10000 lines (not a problem nowadays), so cmd-F in the terminal works pretty well. And I prefer the natural/kinetic scrolling of the terminal backlog to less as a fullscreen tty program. Finally, as the article alludes to, tail can monitor multiple files at once.
- pimlottc 5y ago
  > I love to press enter a few times to add a few empty lines to serve as a marker. Same! If it weren’t for this, I’d use less, as the searchability is often handy. But it’s funny how just one tiny (and possible unintended?) “feature” turns out to be so dang useful that I keep using tail.
  - anyfoo 5y ago
    Yeah, right? It's not even really a "feature" of anything, just an artifact of how teletype support was originally implemented in UNIX, and yet I've been hitting the enter key for my own "marks" for decades.
  - a1369209993 5y ago
    > But it's funny how just one tiny (and possible unintended?) "feature" turns out to be so dang useful that I keep using tail. "Dangling by a trivial feature"[0] seems to be a pretty common issue when people recommend 'better' software. 0: http://prog21.dadgum.com/160.html http://prog21.dadgum.com/160.html
  - ranko 5y ago
    less has its own system of bookmarks: use m followed by a lowercase letter to set a mark and single quote followed by a single letter to jump to that mark. I assume that this means we can have up to 26 bookmarks, though I normally don't go much beyond two.
    - petepete 5y ago
      You can use capital letters in less too, so at least 52.
  - kevincox 5y ago
    I found myself doing this as well and decided to write a simple tool to do it "automatically" for me. You still can't use it with less, but at least it allows you to mark "segments" of the log without switching to that window and mashing enter. https://gitlab.com/kevincox/watchlog https://gitlab.com/kevincox/watchlog
rzzzt 5y ago
tailf is also a good replacement for tail --follow=name, it uses inotify internally to only look at the file when there is a change.
ithkuil 5y ago
And you can also use the & command to filter (out) some patterns, while you're tailing.
ryanmonroe 5y ago
Or hit v after Ctrl-C to open it in a full editor (vi or whatever editor you have as $VISUAL). Quitting the editor resumes tailing.
- asdjlkadsjklads 5y ago
  Okay i wasn't interested in the `less` usage in the GP comment because i use tmux to stop and view logs as they're passing by. However automatically opening in my CLI editor? That sounds sexy as hell!
iamthad 5y ago
Equivalently, one can run `less +F <FILE>`
ian-bateman 5y ago
>couldn’t you pause/unpause the stdout with ctrl-s/ctrl-q instead? edit: child comment is a better solution.
- MawKKe 5y ago
  couldn’t you pause/unpause the stdout with ctrl-s/ctrl-q instead?
- knodi123 5y ago
  uh... doesn't watch just run the command over and over? I would have thought this would just print the entire file every n seconds. Now using tail with that instead of cat....
danielam 5y ago
This reads the entire file, so for large files you'll likely want something like `less -n +F` if you want to use `less`.
emmelaich 5y ago
Another tip for `less`. bind next-file and prev-file to N and P instead of the default :n and :p. Makes it much more convenient to flip through files. [for some reason macos doesn't have the lesskey command even though it has the manual for it. shrug]
rhizome 5y ago
How many times have you seen the last line of a file you're tailing be something like "00:00 Logfile turned over." Both less and tail stop doing their business when a log is rotated and the inode changes. Stop that by adding or extending an alias: alias less='less --follow-name' # still requires <shift>-f to follow alias tail='tail -F'
- aerique 5y ago
  I've been using `tail -F` for decades but I forgot why!
  - gjvc 5y ago
    reopens files replaced with a new inode
- iso1631 5y ago
  I use tail, head, tac, grep, watch etc all the time to pick out stuff I'm looking for, sometimes I use tail -f, but it's certainly a minority of my tail invocations.
c0l0 5y ago
You can stop output on a terminal (emulator) by exercising flow control. If you get overwhelmed by `tail` (or a similar tool's) output, hit ^S. If you are ready to resume, strike ^Q.
bofh23 5y ago
My less(1) tips are: Use "-S" to toggle the "--chop-long-lines" option at invocation or in interactive mode. This mode shows only one line on the screen for each line in a file and is helpful when viewing a log with entries much longer than the screen width. When lines are chopped less(1) lets you scroll horizontally with <LEFTARROW>/<RIGHTARROW>. Chopped mode also works in tail mode ("F" command or "+F" option). As others have mentioned the search "/pattern" and filter "&pattern" commands are awesome and they also work in tail mode. The -J option toggles the status column which is helpful when using search patterns or paging around a file. Since less(1) has lots of features and navigation methods it’s good to remember the "h" command to show the help page.

anyfoo 5y ago

I love to press enter a few times to add a few empty lines to serve as a marker. Plus, I set my terminal scrollback buffer to 10000 lines (not a problem nowadays), so cmd-F in the terminal works pretty well. And I prefer the natural/kinetic scrolling of the terminal backlog to less as a fullscreen tty program. Finally, as the article alludes to, tail can monitor multiple files at once.

pimlottc 5y ago
> I love to press enter a few times to add a few empty lines to serve as a marker. Same! If it weren’t for this, I’d use less, as the searchability is often handy. But it’s funny how just one tiny (and possible unintended?) “feature” turns out to be so dang useful that I keep using tail.
- anyfoo 5y ago
  Yeah, right? It's not even really a "feature" of anything, just an artifact of how teletype support was originally implemented in UNIX, and yet I've been hitting the enter key for my own "marks" for decades.
- a1369209993 5y ago
  > But it's funny how just one tiny (and possible unintended?) "feature" turns out to be so dang useful that I keep using tail. "Dangling by a trivial feature"[0] seems to be a pretty common issue when people recommend 'better' software. 0: http://prog21.dadgum.com/160.html http://prog21.dadgum.com/160.html
- ranko 5y ago
  less has its own system of bookmarks: use m followed by a lowercase letter to set a mark and single quote followed by a single letter to jump to that mark. I assume that this means we can have up to 26 bookmarks, though I normally don't go much beyond two.
  - petepete 5y ago
    You can use capital letters in less too, so at least 52.
- kevincox 5y ago
  I found myself doing this as well and decided to write a simple tool to do it "automatically" for me. You still can't use it with less, but at least it allows you to mark "segments" of the log without switching to that window and mashing enter. https://gitlab.com/kevincox/watchlog https://gitlab.com/kevincox/watchlog

rzzzt 5y ago

tailf is also a good replacement for tail --follow=name, it uses inotify internally to only look at the file when there is a change.

ithkuil 5y ago

And you can also use the & command to filter (out) some patterns, while you're tailing.

ryanmonroe 5y ago

Or hit v after Ctrl-C to open it in a full editor (vi or whatever editor you have as $VISUAL). Quitting the editor resumes tailing.

asdjlkadsjklads 5y ago
Okay i wasn't interested in the `less` usage in the GP comment because i use tmux to stop and view logs as they're passing by. However automatically opening in my CLI editor? That sounds sexy as hell!

iamthad 5y ago

Equivalently, one can run `less +F <FILE>`

ian-bateman 5y ago

>couldn’t you pause/unpause the stdout with ctrl-s/ctrl-q instead? edit: child comment is a better solution.

MawKKe 5y ago
couldn’t you pause/unpause the stdout with ctrl-s/ctrl-q instead?
knodi123 5y ago
uh... doesn't watch just run the command over and over? I would have thought this would just print the entire file every n seconds. Now using tail with that instead of cat....

danielam 5y ago

This reads the entire file, so for large files you'll likely want something like `less -n +F` if you want to use `less`.

emmelaich 5y ago

Another tip for `less`. bind next-file and prev-file to N and P instead of the default :n and :p. Makes it much more convenient to flip through files. [for some reason macos doesn't have the lesskey command even though it has the manual for it. shrug]

rhizome 5y ago

How many times have you seen the last line of a file you're tailing be something like "00:00 Logfile turned over." Both less and tail stop doing their business when a log is rotated and the inode changes. Stop that by adding or extending an alias: alias less='less --follow-name' # still requires <shift>-f to follow alias tail='tail -F'

aerique 5y ago
I've been using `tail -F` for decades but I forgot why!
- gjvc 5y ago
  reopens files replaced with a new inode
iso1631 5y ago
I use tail, head, tac, grep, watch etc all the time to pick out stuff I'm looking for, sometimes I use tail -f, but it's certainly a minority of my tail invocations.

c0l0 5y ago

You can stop output on a terminal (emulator) by exercising flow control. If you get overwhelmed by `tail` (or a similar tool's) output, hit ^S. If you are ready to resume, strike ^Q.

bofh23 5y ago

My less(1) tips are: Use "-S" to toggle the "--chop-long-lines" option at invocation or in interactive mode. This mode shows only one line on the screen for each line in a file and is helpful when viewing a log with entries much longer than the screen width. When lines are chopped less(1) lets you scroll horizontally with <LEFTARROW>/<RIGHTARROW>. Chopped mode also works in tail mode ("F" command or "+F" option). As others have mentioned the search "/pattern" and filter "&pattern" commands are awesome and they also work in tail mode. The -J option toggles the status column which is helpful when using search patterns or paging around a file. Since less(1) has lots of features and navigation methods it’s good to remember the "h" command to show the help page.