Linux to list file with size MB GB TB

 To list files in linux ,will use:

"ls -la "

   >>    –l  displays a list of files and directories in long format and shows the sizes in bytes.

but if you want to see the size into KB, MB, GB, or TB 

"ls -lh"

   >>  –h  scales file sizes and directory sizes into KB, MB, GB, or TB when the file or directory size is larger than 1024 bytes.

Check Linux Heap memmory available

 On Ubuntu:

#java -XX:+PrintFlagsFinal -version | grep -iE 'HeapSize|PermSize|ThreadStackSize'

Enable root user password in ubuntu |Change root password

 In Ubuntu, while installaing you should have created a new user and password.

Login ssh with new user and password.

Change root password using command#

#sudo passwd root

Enter new UNIX password: Retype new UNIX password: passwd: password updated successfully

Now you can login with root .