# Other Linux Commands

1. To know in which groups you are present then you can run
    

`groups`

2. less:- f your content is too large then we need to use `less` command.
    

You can go to the next line by pressing up and down arrow, space bar → to go to the next page, b → go to the previous page, G: go to the end of the line, g: go to the beginning of the line.

3. File System Structure:- In linux the file system structure is arranged in hierarchical manner and it is shown as a tree structure.
    
    /: This is a starting point of Linux is called Root directory.
    
    /bin: It contains binaries executables (commands) used for system booting and repair (eg ls, cp, mv, cat)
    
    /lib: It contains shared libraries which helps to execute the programs stored in /bin and /sbin.
    
    /boot: It contains the files which is required for system booting such as Linux kernel (vmlinuz) and the bootstrap loader configurations.
    
    /dev: It is a device file (a special files) that contain hardware devices which includes USB devices, terminal, hard drives (tty - for terminal, tty/sda1 - for hard drive).
    
    /etc: It contains system wide configurations files including system setting and scripts used by the system programs and services. (ge /etc/passwd for user data)
    
    /media: This is a location where USB drives, DVDs are mounted.
    
    /mnt: A temporary mount file used in file system for mounting additional files.
    
    /opt: A optional packages that does not belong to core OS. for eg third party application.
    
    /proc: A virtual file system that describe about the kernel and running process. Here files which are present are not real files but it represent system and process information (for eg, /proc/cpuinfo shows the CPU details)
    
    /home: This is a default directory for each user’s personal directories which is located at subdirectories. (for eg /home/john)
    
    /root: This is the home directory for root user.
    
    /sbin: It contains system binaries used for system maintenance (fsck, shutdown, mount) by system admin.
    
    /tmp: It contains temporary files which store temporary data. It gets deleted when system reboot.
    
    /var: It contain variable files such as logs (/var/log), mail and spool files for printer and other services.
    
    /usr: It contains read only user data which includes system application, libraries and documntation.