All of us know that the tail command is used for getting the last lines of the file in unix. But the same command can allso be used for monitoring the log files actively, say for example if you want to monitor a log file which is being updated by a process then you can use
‘tail -f filename.ext’
this will show the last few lines of the files but it will not return to the prompt instead it will monitor the file and when ever the file got updated then it will show the updated data in the file.