About the role
- Linux/Unix:
- How do you check disk usage and memory usage?
a. df -h à Shows disk space usage of all mounted filesystems.
b. du -sh à Shows the size of a specific directory
- What does the tail -f command do?
a. Displays the last 10 lines of a file by default
b. -f (follow): Keeps the terminal open and updates the output as new lines are added to the file.
- How do you find the top memory-consuming processes?
a. top command will show all the memory consuming process
- What all details will appear after you execute top command ?
CPU and memory usage
Running processes
Load averages
Swap usage
- Databases:
- How do you check if a DB connection is active?
Will Open SQL developer tool if it is Oracle database then will check by running a simple select statement. Select 1 from dual;
- Can you write a query to find the number of records in a table?
Select count(*) from table
- What is the difference between WHERE and HAVING clauses?
WHERE filters rows before grouping.
HAVING filters groups after aggregation.
- What is the difference between INNER JOIN and LEFT JOIN?
INNER JOIN: Returns only matching rows from both tables.
LEFT JOIN: Returns all rows from the left table and matching rows from the right; unmatched rows show NULLs.
- Application Logs:
- How do you grep for a specific error in a log file?
grep “Error” <filename>
- What is the difference between Incident, Problem, and Change in ITIL terms?
Incident: An unplanned interruption to a service.
Problem: The underlying cause of one or more incidents.
Change: A modification to infrastructure or services to fix problems or improve performance.