Nuclear Powerplant Company Bangladesh Limited(NPCBL)
Post: Assistant Engineer (CSE),
Exam Date: 26-05-2023
#include <iostream> using namespace std; int main() { cout << "Prime numbers between 1 and 100 are:" << endl; for (int num = 2; num <= 100; num++) { bool isPrime = true; for (int divisor = 2; divisor * divisor <= num; divisor++) { if (num % divisor == 0) { isPrime = false; break; } } if (isPrime) { cout << num << " "; } } cout << endl; return 0; }Output:
Prime numbers between 1 and 100 are: 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97
UNIX Commands with Examples
1. File Move (mv)
The mv command is used to move or rename files and directories.
Syntax:
mv [source] [destination]
Example 1: Move a file named example.txt to the documents directory.
mv example.txt documents/
Example 2: Rename a file from oldname.txt to newname.txt.
mv oldname.txt newname.txt
2. Change Directory (cd)
The cd command is used to change the current working directory.
Syntax:
cd [directory_path]
Example 1: Change to the home directory.
cd /home
Example 2: Navigate to the parent directory.
cd ..
Example 3: Return to the home directory.
cd ~
3. Search from a Specific Line (sed or grep)
Using sed: Search for text from a specific line number.
Syntax:
sed -n ‘[line_number],$p’ [file] | grep [search_term]
Example: Search for the word error starting from line 10 in logfile.txt.
sed -n '10,$p' logfile.txt | grep "error"
Using grep with -A: Display lines after a match starting at a specific line.
Example: Search for error starting from line 10.
grep -n "error" logfile.txt | awk -F: '$1 >= 10 {print $0}'