Why does tail-F fail to produce any output?
Note that the following does produce output: I am using tail version 8.21 (GNU coreutils). tail shows the last X lines. tail -f does the same, but essentially in an infinite loop: on start-up, show the last X lines of the file, then using some OS magic (like inotify), monitor and show new lines.
Do you need an end of file for tail?
You need an end-of-file for tail to work in any configuration. head doesn’t have that restriction, it just needs a start of file (which it might not have, try head test.pipe ). Stream oriented tools like sed and awk need neither a start or end of file: they work on buffers.
What’s the difference between tail and tail F?
tail shows the last X lines. tail -f does the same, but essentially in an infinite loop: on start-up, show the last X lines of the file, then using some OS magic (like inotify), monitor and show new lines. To do its job, tail must be able to locate the end of the file.
Why does ” tail ” fail to produce any lines?
To do its job, tail must be able to locate the end of the file. If tail cannot find the file’s end, it cannot show the last X lines, because “last” is undefined. So what does tail do in this case?
How to do tail command in Linux with examples?
Let us consider two files having name state.txt and capital.txt contains all the names of the Indian states and capitals respectively. Without any option it display only the last 10 lines of the file specified.
What’s the difference between GNU tail and tail-F?
If you go back to the first shell session and type something more, that output will immediately be shown by tail in the second shell session. and type something, a few lines. With GNU tail, these lines will not show up in the second shell session (where tail -f is still running). Repeat the exercise with tail -F and observe the difference.
How big of a buffer does GNU tail have?
GNU tail can output any amount of data (some other versions of tail cannot). It also has no -r option (print in reverse), since reversing a file is really a different job from printing the end of a file; BSD tail (which is the one with -r) can only reverse files that are at most as large as its buffer, which is typically 32 KiB.