BOS (basics of operating system)
A microproject of Linux commands that ask the user for input and give a
maximum of 3 attempts
Submitted to
VPMP Polytechnic, Gandhinagar
Department of Computer Engineering
Guide Name:
Mrs. K. H. Mistry
Prepared By:
Shubham Prajapati
(226540307162)
Yana Makadia (226540307210)
Krish Patel (226540307128)
Yuvraj Solanki (226540307186)
 Case study on a shell script (linux shell script) that asks the user
for a password until it is correct and gives a maximum of 3
attempts.
 Here, a shell script is written that asks the user for input until it
is correct and gives a maximum of 3 attempts.
 Here, the password is Bos. System will ask the user for a
password, if that entered password is correct, it’ll return
“Access granted. Welcome!”
 If the entered password is incorrect, then the system will
return “Incorrect password" and will return the number of
attempts remaining.
 Step wise explaination of script:
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
Step 1: Open Cygwin Terminal 64.

Step 2: In Cygwin terminal 64, the command to open or create
a new file is “vi filename.sh” In this command to open the vi
editor, filename is the file to be created or opened. Here we
named our file "project.sh”.

Step 3: After opening the project.sh file, we’ll write a script.

Step 4: After that, we will compile that script and execute it.

Step 5: To quit Vi Editor with changes, we use “esc then ZZ.”

Step 6: After quitting Vi Editor, we will compile the script. To
compile the script, the command is “chmod u+x filename.sh”,
As our filename is project.sh, we will write “chmod u+x
project.sh”.

Step 7: After compile script we will execute it using
"./filename.sh." As our filename is project.sh, we will write
“./project.sh”.

Step 8: If our script has no errors, it will be executed
successfully.
Bos case study on shell script
 Use of commands that we have used:
 -gt: In Linux, the “-gt” command is used as greater than.
 read: In Linux, the “read” command is used for taking input
from the user.
 -p: In Linux, “-p” is used with the read command to display the
prompt and store entered values in variables.
 fi: In Linux, “fi” is used to terminate a selection statement.
 -eq: In Linux, “-eq” is used as an equal’s operator.
 esc then ZZ: In Linux, “esc then ZZ” is used for quit vi editor
with changes.
 Used commands in execution of the script:
 chmod u+x project.sh: In Linux, this command is used
to debug the script.
 ./project.sh: In Linux, this command is used to
run/execute the script.
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Bos case study on shell script
 Script:
 Script Output:
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Bos case study on shell script