Linux Administration

In Linux the file system is based on one root directory, or hierarchical top point with subdirectories below it. In which each sub-directories has its own importance like some act as mount points, some for log messages, some for all hardware devices etc. You can find a brief description of all the directories and sub directories below: / : Its the top most directory in any of the Unix based system. /bin : Essential command binaries that need to be available in single user mode; for all users, e.g. , cat, ls, cp. / boot : Boot loader files, e.g. , kernels, initrd etc. /dev : Information of all the hardware devices. /etc : All the config files. /home : Home directories of all the users in a particular machine. /media : Mount points for removable media such as USB, CD etc. /mnt : For temporary mount points. /opt : Optional software packages like openoffice etc. /root : Home directory of root user. /sbin : System binaries like init, ip etc. /tmp : Temporary files. Ofte...

Single user mode is a mode in which a multiuser computer operating system boots into a single superuser. It is mainly used for maintenance of multi-user environments, Basically single user mode in unix based systems is known as runlevel 1. Some tasks may require exclusive access to shared resources, for example running fsck on a network share or to retrieve a lost superuser password or any maintenance task. For gaining access to #(root) prompt what you need to do is ? Once your machine is booting, for getting access to # prompt your just need to edit the bootloader i.e. in case of RHEL6 its GRUB (GRand Unified Bootloader).  Once your machine is booting just press a key couple of time so that you are brought to the GRUB menu. The GRUB menu appears like the image shown below: The values which are show in this window are the kernerl(s) which are installed in your machine. Use the cursor keys to switch between kernels (if you have mo...