How does the "tail" command's "-f" parameter work?
$ tail -f testfile
the command is supposed to show the latest entries in the specified file, in real-time right? But that's not happening. Please correct me, if what I intend it to do is wrong...
I created a new file "aaa" and added a line of text and closed it. then issued this command (first line):
$ tail -f aaa xxx xxa axx
the last three lines are the contents of the file aaa. Now that the command is still running (since I used
-f), I opened the file aaa via the GUI and started adding a few more lines manually. But the terminal doesn't show the new lines added in the file.
What's wrong here? The
tail -fcommand only shows new entries if they are written by system only? (like log files etc)
With --follow (-f), tail defaults to following the file descriptor, which means that even if a tail’ed file is renamed, tail will continue to track its end. This default behavior is not desirable when you really want to track the actual name of the file, not the file descrip- tor (e.g., log rotation). Use --follow=name in that case. That causes tail to track the named file in a way that accommodates renaming, removal and creation.
Your text editor is renaming or deleting the original file and saving the new file under the same filename. Use
worked! So, I can use `$ tail -F filename` command all the time instead of `$ tail -f filename` right?
*If* that's your intended behavior. There *may* be cases where you want to follow by descriptor instead of filename, but to be fair I haven't come across many of those.