How to use `tail` command?

The tail command is used to display the end portion of a file. Here are some common usages:

Display the last 10 lines of a file (default behavior):
```
tail filename.txt
```
Display a specific number of lines:
To display the last 5 lines of a file:
```
tail -n 5 filename.txt
```
Display lines starting from a specific line number:
To display lines starting from line 10:
```
tail -n +10 filename.txt
```
Follow a file in real-time (useful for log files):
To continuously monitor a file for new lines:
```
tail -f filename.txt
```
Combine with other commands:
You can pipe the output of tail to other commands. For example, to count the number of lines in the last 10 lines of a file:
```
tail filename.txt | wc -l
```

These examples should help you get started with using the tail command effectively.