(following options output by tail --help)

Usage: tail [OPTION]... [FILE]...
Print the last 10 lines of each FILE to standard output.
With more than one FILE, precede each with a header giving the file name.
With no FILE, or when FILE is -, read standard input.

Mandatory arguments to long options are mandatory for short options too.

      --retry           keep trying to open a file even if it is
                           inaccessible when tail starts or if it becomes
                           inaccessible later; useful when following by name,
                           i.e., with --follow=name
  -c, --bytes=N    output the last N bytes
  -f, --follow[={name|descriptor}]
                           output appended data as the file grows;
                           -f, --follow, and --follow=descriptor are
                           equivalent
  -F                     same as --follow=name --retry
  -n, --lines=N     output the last N lines, instead of the last 10
      --max-unchanged-stats=N
                           with --follow=name, reopen a FILE which has not
                           changed size after N (default 5) iterations
                           to see if it has been unlinked or renamed
                           (this is the usual case of rotated log files)
      --pid=PID       with -f, terminate after process ID, PID dies
  -q, --quiet, --silent    never output headers giving file names
  -s, --sleep-interval=S   with -f, sleep for approximately S seconds
                           (default 1.0) between iterations.
  -v, --verbose     always output headers giving file names
      --help     display this help and exit
      --version  output version information and exit

If the first character of N (the number of bytes or lines) is a `+',
print beginning with the Nth item from the start of each file, otherwise,
print the last N items in the file.  N may have a multiplier suffix:
b 512, k 1024, m 1024*1024.

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 descriptor (e.g., log
rotation).  Use --follow=name in that case.  That causes tail to track the
named file by reopening it periodically to see if it has been removed and
recreated by some other program.
 

Examples
Here are a few examples of how to use tail.

This example will show the last 20 lines instead of the default 10:
tail --lines=20 /var/log/httpd/error_log

This example will show the last 1024 bytes (1KB):
tail --bytes=1024 /var/log/httpd/error_log

This example will show results in real time:
tail --follow /var/log/httpd/error_log