输出文件的末尾部分
tail --help
[root@node0 ~]# tail --help
Usage: tail [OPTION]... [FILE]...
Print the last 10 lines of each FILE to standard output. 默认输出文件末尾10行
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.
-c, --bytes=K output the last K bytes; alternatively, use -c +K
to output bytes starting with the Kth of each file
-f, --follow[={name|descriptor}] 当文件增长时,输出后续添加的数据
output appended data as the file grows;
-f, --follow, and --follow=descriptor are
equivalent
-F same as --follow=name --retry
-n, --lines=K output the last K lines, instead of the last 10; 输出最后N行,而非默认的最后10行
or use -n +K to output lines starting with the Kth
--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).
With inotify, this option is rarely useful.
--pid=PID with -f, terminate after process ID, PID dies
-q, --quiet, --silent never output headers giving file names
--retry keep trying to open a file even when it is or
becomes inaccessible; useful when following by
name, i.e., with --follow=name
-s, --sleep-interval=N with -f, sleep for approximately N seconds
(default 1.0) between iterations.
With inotify and --pid=P, check process P at
least once every N seconds.
-v, --verbose always output headers giving file names
--help display this help and exit
--version output version information and exit
示例：
tail –f /var/log/messages
tail –n 100 /var/log/messages