Exploring The System

Question 2

How do you list the content of a directroy?

Answer 2

ls

Question 3

How do you determine a file type?

Answer 3

file filename

Question 4

How can you veiw the contents of a file?

Answer 4

less

Question 5

How do we change the format of a commands output?

Answer 5

We change the format of a command output by using Options and Arguments.

Question 6

How do list the content of multiple directories?

Answer 6

ls ~ /usr /var Issue a ls to tell the system to list the content of each directory listed seperated by a space

Question 7

What does ls -a (–all) do?

Answer 7

List all files, even those that begin with a period, which are normally hidden

Question 8

What does ls - l do?

Answer 8

Displays results in long form

Question 9

What does ls - d (–directory) do?

Answer 9

When used in conjunction with -l it will list the details of the direcotry rather than its contents

Question 10

What does ls -h (human-readable) do?

Answer 10

In long form listing, displays the file size in human readable format rather than bytes.

Question 11

What does ls -F (–classify) do?

Answer 11

This option appends an indicator character to the end of each listed name.

Question 12

What does ls -r (–reverse) do?

Answer 12

Displays results in reverse order.

Question 13

What does ls -s do?

Answer 13

Sorts by file size.

Question 14

What does ls -t do?

Answer 14

Sorts by modification time.

Question 15

What is a common ls command with options

Answer 15

ls -ltr This will show the contents of a directory in long format sorted by time then display in reverse order.

Question 16

What are some of the common ways to navigate less

Answer 16

“Page up or b Scroll back one page”
“Page Down or space Scroll forward one page”
“Up Arrow” Scroll up one line”

Question 17

How can we view the contents of a text file?

Answer 17

less

Question 18

/

Answer 18

The root directory. Where everything begins.

Question 19

/bin

Answer 19

Contains binaries (programs) that must be present for the system to boot and run.

Question 20

/boot

Answer 20

Contains the Linux kernel, initial RAM disk image (for drivers needed at boot time), and the boot loader.

Question 21

/boot/grub/grub.conf or menu.lst

Answer 21

used to configure the boot loader

Question 22

/boot/vmlinuz

Answer 22

the linux kernel

Question 23

/etc

Answer 23

The /etc directory contains all of the system-wide configuration files. It also contains a collection of shell scripts which start each of the system services at boot time. Everything in the directory should be readable text.

Question 24

/etc/crontab

Answer 24

A file that defines when automated jobs will run

Question 25

/dev

Answer 25

This is a special directory which contains device nodes. “Everything is a file” also applies to devices. Here is where the kernel maintains a list of all the devices it understands.

Question 26

/etc/fstab

Answer 26

a table of storage devices and their associated mount points

Question 27

/etc/passwd

Answer 27

a list of the user accounts

Question 28

/lib

Answer 28

Contains shared library files used by the core system programs. These are similar to DLLs in Windows.

Question 29

/home

Answer 29

In normal configurations, each user is given a directory in /home. Ordinary users can only write files in the home directories. This limitation protects the system from errant user activity.

Question 30

/lost+found

Answer 30

Each formatted partition or device using a Linux file system such as ext3, will have this directory. It is used in the case of a partial recovery from a system corruption event. Unless something really bad has happened to your system this directory will remain empty.

Question 31

/media

Answer 31

On modern Linux systems the /media directory will contain the mount points for removable media such as USB drives CD-ROMs, etc. that are mounted automatically at insertion.

Question 32

/opt

Answer 32

The /opt direcotry is used to install "optional" software. This is mainly used to hold commercial software products that may be installed on your system.

Question 33

/proc

Answer 33

The /proc directory is special. It's not a real file system in the sense of files stored on your hard drive. Rather, it is a virtual file system maintained by the Linux Kernel. The "files" it contains are peepholes into the kernel itself. The files are readable and will give you a picture of how the kernel sees your computer.

Question 34

/mnt

Answer 34

On older Linux systems, the /mnt directory contains mount points for removable devices that have been removed manually.

Question 35

/root

Answer 35

This is the home directory for the root account

Question 36

/sbin

Answer 36

This directory contains "system" binaries. These are programs that perform vital system task that are generally reserved for the superuser.

Question 37

/tmp

Answer 37

The /tmp directory is intended for the storage of temporary, transient files created by various programs. Some configurations cause this directory to be emptied each time the system is rebooted.

Question 38

/usr

Answer 38

The /usr directory tree is likely the largest one on a Linux system. It contains al the programs and support files used by regular users.

Question 39

/usr/bin

Answer 39

/usr/bin contains the executalbe programs installed by you linux distrobution. It is not uncommon for this directory to hold thousands of programs.

Question 40

/usr/lib

Answer 40

The shared libraries for the programs in /usr/bin

Question 41

/usr/sbin

Answer 41

Contains more system administration programs

Question 42

/usr/local

Answer 42

The /usr/local tree is where programs that are not included with your distorbution but are intended for system wide use are installed. Programs compied from source code are normally installed in /usr/local/bin . On a newly installed Linux system, this tree exists, but will be empty until the system administrator puts something in it.

Question 43

/usr/share

Answer 43

/usr/share contains all the shared data used by the programs in /usr/bin. This includes things like default configuration files, icons, screen backgrounds, sound files, etc.

Question 44

/usr/share/doc

Answer 44

Most packaged installed on the system will include some kind of documentation. In /usr/share/doc, we will find documentation files organized by package.

Question 45

/var

Answer 45

With the exception of /tmp and /home, the directories we have looked at so far remain releatively static, that is, their contents don't change. The /var directory tree is where data that is likely to change is stored. Various databases, spool files, user mail, etc. are located here.

Question 46

/var/log

Answer 46

/var/log contains log files, records of various system activity. These are very important and should be monitore from time to time. The most useful one is the /var/log/messages. Note that for security reason on some systems, you must be supersuser to veiw log files.