Is there any in-built Linux command to display the contents of a directory in real-time?

Is there any in-built Linux command to display the contents of a directory in real-time?Similar to the "tail -f file_name" command which displays the contents of a file in real-time.

you can do this using watch. It is not completely real-time, but close enough (up to a tenth of a second):

watch -n0.1 ls

from the manual:

-n, --interval seconds
          Specify update interval.  The command will not allow quicker than 0.1 second interval, in which the smaller values are converted.

I wrote this, I hope this is what you needed. It's not a built-in Linux command, but it uses only common programs present in most UNIX boxes.

Adjust sleep time as needed. I would use a value of at least 2 seconds. Use cmd="ls" for non-recursive structure or cmd="find DIRNAME" to search recursively. Note that in the last case, you will get a DIRNAME/ prefix to all files and directories.

 echo "" | awk '{while ( 1 ) {cmd="find ."; delete b;c=0; while ( ( cmd | getline result ) > 0 ) {test=1;c++;n=0;for (i in a) {n++;if (a[i]==result) {b[c]=i; test=0; break;}} if (test) {n++;a[n]=result;b[c]=n;print "##NEW## "result }} close (cmd); for (i in a) {test=1;for (j in b) {if (b[j]==i) {test=0;break}} if (test) {print "##DELETED## "a[i]; delete a[i]}} system("sleep 5") } }'