I want to know how to tail a log file when lines in the files are updating(appending and removing)?
As Atari911 said, you can use
watch along with
cat to do this. Use
watch cat <filename>
this will output the contents of the file given by
filename every 2 seconds to standard output. To change the interval for updating the output to something like 1 second(you can't reduce beyond 0.1), you can use
watch -n 1 cat <filename>
I am using cat to output the complete file, you could tail but that would only give you the last
n lines of the file, where
n is 10 by default.
Refer to the manual page of watch for more info.
You need to use the tail command which output the last part of files in real time including all incoming logs to a standard output device such as screen. the commadn to use is
tail -f /path/to/log/file
EDIT: TRY this
tail -f --retry /path-to-log-file
This will try to reopen the file with the new contents
tail -F /path/to/log/file