linux
January 10, 2019
What is TAIL in Linux and how you should use it!
You might wonder 'how do I get the last lines of a log file' or 'how do I get new lines written to a file in linux'. Well tail is what you need!
What is tail?
Tail is a program which Outputs a number of lines from a file depending on what arguments you call it with. There are quite a few arguments you can add but the core what is useful is below.
Usage
You can invoke tail but where it really shines is in a pipe operation.
Last 5 lines
./someFile.txt | tail -n 5
To print any new lines
./someFile.txt | tail -f
Useful Arguments to Remember
| ARG | Name | Action |
|---|---|---|
| -f | follow | output new lines on the end |
| -F | follow and retry | follow and retry if the file is inaccessible |
| -n # | number | number of lines to output when the command is run |
| + # | number of lines to output at the start of the file | |
| - # | number of lines to output at the end of the file |
Thanks for reading!