LINUX TAIL指令

介紹

tail指令用來檢視檔案的最後十行。

語法

tail [options] [files]

常用的options

-n N   Print the last N lines of the file instead of 10.

-N     Same as -n N.

-n +N  Print all lines except the first N.

-c N   Print the last N bytes of the file.

-f     Keep the file open, and whenever lines are appended to the file, print them. This is extremely useful. Add the --retry option if the file doesn't exist yet, but you want to wait for it to exist.

-q     Quiet mode: when processing more than one file, don't print a banner above each file. Normally tail prints a banner containing the filename.

範例

你可以檢視檔案的最後十行：

⤍ tail myfile

搭配nl指令及管線，可以顯示行數：

⤍ nl myfile | tail

使用-f選項，會讓tail指令持續讀取檔案，只要新資料被寫入，就會馬上顯示出來，常被用來讀取log files：

⤍ tail -f /var/log/syslog