linux blog
Linux Blog Writing
Name :- Tanuja Tidake
PRN :- 202501040063
Div :- CS1
Batch :- C13
Linux is Free and open-source means operating system allowed user to view, modify, distributed it source code no cost, fully customizable.
Linux is highly secure means fewer viruses and strong permission.
Linux is faster performance like works even on old or low spec systems.
Linux is good for servers, stable and reliable.
Linux is great for programming for supports all major languages and tools.
It is use everywhere like servers, Android, cloud and supercomputer.
All Commands with Syntax, Use and Scennio
1) ls
Syntax :- ls -l
Scenario 1 :- show the all files in your directory
Scenario 2 :- Show only directories
2) echo
Syntax :- echo
Scenario 1 :- I want to display my name
Scenario 2 :- Print your marks
3) read
Syntax :- read
Scenario 1 :- To read the variable name
Scenario 2 :- To read the user name
4) cd
Syntax :- cd directory name
Scenario 1 :- Mam said that move to the linux 2025 directery
Scenario 2 :- Go directory to the home directory
5) mkdir
Syntax :- mkdir directory name
Scenario 1 :- You want to create folders for assignments and notes.
Scenario 2 :- Neha want to create subfolders
6) chmod
Syntax :- chmod +x filename.sh
Scenario 1 :- You want to be creat a file like notes.txt and display the given file
Scenario 2:- I want to create file for mall management and I gives a permission for execution
7) touch
Syntax :- touch filename
Scenario 1 :- Priya make a file for his daily routine by using touch command
Scenario 2 :- The CEO is starting a new project inside his project folder,he needs to create several empty files
8) cat
Syntax :- cat filename.sh
Scenario 1 :- Mihir creat file like Song.txt and he display the all songs inside the file.
Scenario 2 :- Most of the time user use a cat command to display the conent of file
9) sed
Syntax :- sed [option] 'script' [file]
Scenario 1 :- delete line numbes 5 from a file
Scenario 2:- I want to remove all entries of employes who have left the company & marked as "Resigned"
10) head
Syntax:- head -n filenam
Scenario 1 :- The group are writing a program that generate output in output.txt and want to check only the top few lines to confirm a format
Scenario 2 :- I want to read 10 lines inside the data.txt
11) tail
Syntax :- tail -n filename
Scenario 1:- Mam want to be check last 10 entries from student record file.
Scenario 2 :- I want to check last 3 lines to confirm the end statement
12) grep
Syntax:- grep -i "___" filename | wc -l
Scenario 1:- I want to know the exact line numbers where "Linux" appears in pt.txt
Scenario 2 :- Manager want to find all employes who work in the sales department
13) cp
Syntax :- cp filename
Scenario 1 :- Mahima want to copy program into the given directory.
Scenario 2 :- In Hospital nurse create a new directory called backup and she want to copy the file there
14) clear
Syntax :- clear
Scenario 1 :- Students enter in lab then they removes all previous text and gives a fresh terminal
Scenario 2 :- There are most of the error on the terminal I want to clear terminal
15) date
Syntax :- date
Scenario 1 :- display a day, month and time in the pattern like hour : minute : second.
Scenario 2 :- If your system clock is wrong. you can check it using date command
16) cal
Syntax :- cal [ month ] [ year]
Scenario 1 :- The small child was interested to see new calendar
Scenario 2 :- Amit want to see a june month
17) file *
Syntax :- file *
Scenario 1 :- I received a file name report.txt,but it is not open
18) If Else
Syntax :- if [ condition ]
then
logic
else
logic
fi
Use :- It is decision making statement
Scenario :- Mam gives a program for student take positive integer and tell if it is divisible by 5 or not
echo "Enter a number: "
read n
if [ $((n%5)) == 0 ]
then
echo " divisible by 5 "
else
echo " not divisible by 5 "
fi
19) While loop
Syntax:- while [ contion ]
do
logic
done
Use :- While loop is used to iteration like repeat a block of commands multiple times.
Scenario :- I want to display multiples of 3 up to 30.
i = 3
while [ $i -le 30 ]
do
echo "$1"
i = $(( i+3))
done
20) for loop
Syntax :- for variable in { start .. end }
do
logic
done
Use :- repeat a set of commands.
Scenario :- I want to print even numbers.
for i in { 2.. 20..2 }
do
echo" $i"
done
21 ) Continue
Syntax :- Continue
Use :- Inside loops to skip the remaining commands in the current iteration and jump to the next iteration of the loop.
Scenario :- Print numbers from 1 to 20, but skip the number 10
for num in { 1..20 }
do
if [ $num -eq 10 ]
then
continue
fi
echo "$num"
done
22) Break
Syntax :- break
Use :- to stop the execution of a loop
Scenario :- Sir want to search for a file named entry.txt in a directory .It is found, stop checking other files.
for file in *
do
if [ "$file" = "enty.txt"]
then
echo " File found : $file"
break
fi
done
23) String Concatenation
Syntax :- str3 = "$ str1 $ str 2"
Use :- Combine two or more strings.
Scenario :- In hospital stores patient name by joining first name and last name. Combine the two names and display the full name.
Str1 = "Mansi"
str2 = " Nikam"
fullname = "$str1 $str2"
echo "Full Name: $fullname"
24) String Comparison
Syntax :- variable =~ variable
Use :- decision making inside scripts and checking empty or non-empty strings
Scenario :- The manager wants to check if the name of two staff is same
s1 = " seema"
s2 = " reema "
if [ $s1 =~ $s2 ]
then
echo " same "
else
echo " not same"
fi
Conclusion
Use of command
1) ls :- lists the contents of a directory
2) echo :- display on terminal
3) cd :- change the current directory
4) mkdir :- make a directory
5) chmod :- permission for execution
6) touch :- creating a new file
7) cat :- display the content of file
8) sed :- perform various transformation on text
9) head :- display the beginning lines of a file
10) tail :- display the ending lines of a file
11) grep :- searching for patterns in files
12) cp :- for copy
13) clear :- clear a teminal screen
14) date :- display or set system date and time
15) read :- to read or show the input
16) cal :- to show the regular calendar month
17) file * :- list the all files in current directory
18) mv :- to move the files and directories from one to another
19 ) rm :- remove the files and directories
20) pwd :- print the full path of the current working directory
21) whoami :- to check the current user login
22) if else :- it is decision making statement
23) while loop :- while loop is used to iteration like repeat a block of commands multiple times
24) for loop :- repeat a set of commands
25) continue :- inside loops to skip the remaining commands in the current iteration and jump to the next iteration of the loop
26) break :- to stop the execution of a loop
27) string concatenation :- combined two or more strings
28) string Comparison :- decision making inside scripts and checking empty or non- empty string
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