2. What is OS?
● An operating system (OS) is a collection of
software(Programs) that manages computer
hardware resources .
● It is an interface between a computer user and
computer hardware.
3. What is Linux?
● Linux is a Kernel.(core part of linux based OS)
- It is open source.
- its source code is freely available.
- It is free to use.
4. History of Linux
Unix - Ken Thompson and Dennis Ritchie
GNU project - Richard Stallman – FSF - GNU General Public License(GPL)
Linux - Linus Torvalds
10. Terminal and command
● We manage linux using commands.
command [options] [arguments]
● Use an application called terminal to pass commands
to the operating system.
Application--->System Tools--->Terminal.
11. Basic Commands
1. # uptime
- The uptime command prints the current time
- The duration of time the system has been up
- The number of users online.
- The load average.
[ Linux keeps uptime information in /proc/uptime]
2. # date
- Display date & time.
3. # cal
- Display a calendar.
# cal 12 07 1994
4. # clear
- Clear terminal screen
12. Basic Commands
5. # echo
- This command will echo whatever you provide it.
6. # whatis [command name]
- This command gives a one line description about the
command.
7. # man [command name]
- To see a command's manual page.
8. # info [command name]
- These are like web pages. Internal links are present
within the info pages.
13. Basic Commands
6. # whoami
- This command reveals the user who is currently logged in.
7. # cd [path-to-directory]
- Change the current working directory to the directory
provided as argument.
8. # pwd (Print Current working directory)
- The current directory can be checked with ‘pwd’ command
14. Basic Commands
● Fields of # ls -l or # ll command.
drwxr-xr-x 2 root root 4096 2016-07-06 12:52 files
type
Accesmode
/permission
No:of links/
Shortcuts
owner
group
size Modification date and time
Name
U G O
15. Basic Commands
1. # ls -la - To list hidden files.
2. # ls -ld - To list the properties of a director.
3. # ls -lh - The size is converted into kilo/Mega
bytes.
4. # ls -lr - List in reverse of alphabetical order.
5. # ls -lS - To sort in term of size.
6. # ls -lSr -List in reverse form of size.
7. # ls -lt – List based on time.
16. Basic Commands
10. # touch [filename].[extension]
- For creating an empty file.
- If a file already exists, touch will update its
time stamp.
11. # nano [filename]
- To write and modify the content of a file.
12. # cat [filename]
- used to concatenate one or more files and print the result to the
standard output
- Cannot modify the content.
13. # vim [filename]
14. # vi [filename]
17. Basic Commands
15. # mkdir [directory name]
- to create a directory.
# mkdir -p – to create parent directory
16. # rm
- To remove a file or directory
# rm -f [filename] – forcefully remove
# rm -rf [file or directory name]
18. Basic Commands
17. # cp [source path] [destination path]
# cp -r – to copy directory.
18. # mv [source path] [destination path]
19. # head [filename]
# head -n5 [filename] -to print the first 5 lines
20. # tail [filename]
# tail -n5 [filename] -to print the last 5 lines
19. Basic Commands
21. # wc [filename] -word count
# wc -l [filename] – Total lines.
# wc -w [filename] – Total words.
# wc -c [filename] – Total characters.
22. # cd -Change working direstory.
# cd . - working directory itself.
# cd .. - Parent directory
# cd ../..
23. # rmdir – to remove empty directory.
24. # history – To view the history of commands.
25. # halt – To terminate the system.
