#Bash 的 tail 命令
tail [OPTION]... [FILE]...
功能
查看文件的末尾。
类型
可执行文件（/usr/bin/tail），属于 coreutils。
参数
OPTION选项：-c,--bytes=[+]NUM- 查看文件末尾的NUM字节，如果使用正号，则表示查看第NUM字节之后的内容-f,--follow[={name|descriptor}]- 跟随文件，当文件内容增加时打印追加的内容-F- 等价于--follow=name --retry-n,--lines=[+]NUM- 查看文件末尾的NUM行，如果使用正号，则表示查看第NUM行之后的内容--max-unchanged-stats=N- 使用-f选项选项时，如果连续N次读取文件不变，则尝试重新打开文件--pid=PID- 使用-f选项选项时，当PID进程结束时停止此命令-q,--quiet,--silent- 不打印包含文件名在内的头部信息--retry- 如果文件无法打开，则重新尝试打开-v,--verbose- 打印包含文件名在内的头部信息-z,--zero-terminated- 以空字符（\0）作为行的结尾，而不是换行符（\n）--help- 显示帮助--version- 显示版本
FILE- 文件列表，如果没有这个参数或指定为-，则读取标准输入
#示例
基本功能
$ man tail | tail -n 5 # 查看末尾 5 行
Full documentation <https://www.gnu.org/software/coreutils/tail>
or available locally via: info '(coreutils) tail invocation'
GNU coreutils 9.4 April 2024 TAIL(1)
$ man tail | tail -n +90 # 显示第 90 行之后的内容
There is NO WARRANTY, to the extent permitted by law.
SEE ALSO
head(1)
Full documentation <https://www.gnu.org/software/coreutils/tail>
or available locally via: info '(coreutils) tail invocation'
GNU coreutils 9.4 April 2024 TAIL(1)
监听日志
$ tail -f /var/log/syslog # 监听该文件，文件内容更新时打印追加的内容
2025-11-15T08:30:00.190259+00:00 dev systemd[1]: Finished sysstat-collect.service - system activity accounting tool.
2025-11-15T08:35:01.817178+00:00 dev CRON[3239701]: (root) CMD (command -v debian-sa1 > /dev/null && debian-sa1 1 1)
2025-11-15T08:40:00.422316+00:00 dev systemd[1]: Starting sysstat-collect.service - system activity accounting tool...
2025-11-15T08:40:00.435212+00:00 dev systemd[1]: sysstat-collect.service: Deactivated successfully.
2025-11-15T08:40:00.435761+00:00 dev systemd[1]: Finished sysstat-collect.service - system activity accounting tool.
2025-11-15T08:45:01.832707+00:00 dev CRON[3241555]: (root) CMD (command -v debian-sa1 > /dev/null && debian-sa1 1 1)
2025-11-15T08:50:00.422442+00:00 dev systemd[1]: Starting sysstat-collect.service - system activity accounting tool...
2025-11-15T08:50:00.434650+00:00 dev systemd[1]: sysstat-collect.service: Deactivated successfully.
2025-11-15T08:50:00.435219+00:00 dev systemd[1]: Finished sysstat-collect.service - system activity accounting tool.
2025-11-15T08:55:01.848254+00:00 dev CRON[3243092]: (root) CMD (command -v debian-sa1 > /dev/null && debian-sa1 1 1)
#相关命令
#推荐阅读
#手册
TAIL(1) User Commands TAIL(1) NAME tail - output the last part of files SYNOPSIS tail [OPTION]... [FILE]... DESCRIPTION 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. -c, --bytes=[+]NUM output the last NUM bytes; or use -c +NUM to output starting with byte NUM of each file -f, --follow[={name|descriptor}] output appended data as the file grows; an absent option argument means 'descriptor' -F same as --follow=name --retry -n, --lines=[+]NUM output the last NUM lines, instead of the last 10; or use -n +NUM to skip NUM-1 lines at the start --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 if it is inaccessible -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 -z, --zero-terminated line delimiter is NUL, not newline --help display this help and exit --version output version information and exit NUM may have a multiplier suffix: b 512, kB 1000, K 1024, MB 1000*1000, M 1024*1024, GB 1000*1000*1000, G 1024*1024*1024, and so on for T, P, E, Z, Y, R, Q. Binary prefixes can be used, too: KiB=K, MiB=M, and so on. 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 re‐ ally 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 in a way that accommodates renaming, re‐ moval and creation. AUTHOR Written by Paul Rubin, David MacKenzie, Ian Lance Taylor, and Jim Mey‐ ering. REPORTING BUGS GNU coreutils online help: <https://www.gnu.org/software/coreutils/> Report any translation bugs to <https://translationproject.org/team/> COPYRIGHT Copyright © 2023 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>. This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. SEE ALSO head(1) Full documentation <https://www.gnu.org/software/coreutils/tail> or available locally via: info '(coreutils) tail invocation' GNU coreutils 9.4 April 2024 TAIL(1)