red hat linux 7 chapter2

The Linux File System Hierarchy

/  : is the root directory at the top of the file system hierarchy
   /usr : installed software , shared libraries, include files, and static read-only program data
      /usr/bin :   User commands
      /usr/sbin :  System administration commands
      /usr/local : Locally customized software
   /etc  : Configuration files specific to this system
   /var : Variable data specific to this system that should persist between boots,
   /run : Runtime data for processed started since the last boot, This includes process ID files and lock               files, among other things.
   /home : Home directory where regular users store their personal data and configuration files
   /root : home directory for the administrative superuser, root.
   /tmp : A world-writable space for temporary files. Files which are more than 10 days old are                         deleted from this directory automatically
   /boot : Files needed in order to start the boot process.
   /dev   : Contains special device files which are used by the system to access hardware


commonly used commands

#pwd        //the pwd command displays the full path name of the current location
#ls            //the ls command lists directory contents for the specified directory
#cd           //the cd command to change directory
#touch      //the touch command normally updates a files timestamp to the current data and time                            without otherwise modifying it,This is useful for creating empty files
#ls             //the ls command has multiple options for displaying attributes on files.
                   -l(ling listing format), -a (all files, includes hidden files), -R (recursive ,to include the                            contents of all subdirectories).
#mkdir      //the mkdir command creates one or more directories or subdirectories.
                   the -p parent option creates missing parent directories for the requested destination.