RHEL/UNIX/Linux/Solaris Interview Questions for Oracle DBAs
1. What’s the difference between soft link and hard link?
Ans:
A symbolic (soft) linked file and the targeted file can be located on the same or different file system while for a hard link they must be located on the same file system, because they share same inode number and an inode table is unique to a file system, both must be on the same file system.
2. How you will read a file from shell script?
Ans:
while read line
do
echo $line
done < file_name
3. What’s the use of umask?
Ans:
Will decide the default permissions for files.
4. What is the default value of umask?
Ans:
022
5. What is crontab and what are the arguments?
Ans:
The entries have the following elements:
field allowed values
----- --------------
minute 0-59
hour 0-23
day of month 1-31
month 1-12
day of week 0-7 (both 0 and 7 are Sunday)
user Valid OS user
command Valid command or script
? ? ? ? ? command
| | | | |_________day of the week (0-6, 0=Sunday)
| | | |___________month (1-12)
| | |_____________day of the month (1-31)
| |_______________hour (0-23)
|_________________minute (0-59)
6. How to find operating system (OS) version?
Ans:
uname –a
7. How to find out the run level of the user?
Ans:
uname –r
8. What is load average ?
Load Average is the value which represents the load on the system for a specific period of time. Also it can be considered the ratio of the number of active tasks to the number of available CPUs.
run queue length - the sum of the number of processes that are currently running plus the number that are waiting (queued) to run.
9. What is top command?
Ans:
top is a operating system command, it will display top processes which are taking high cpu and memory.
10. How to delete 7 days old trace files?
Ans:
find ./trace –name *.trc –mtime +7 –exec rm {} \;
11. How to get 10th line of a file (by using grep)?
12. (In Solaris) how to find out whether it’s 32bit or 64bit?
13. What is paging?
15. How to find out the status of last command executed?
Ans:
$?
16. How to find out number of arguments passed to a shell script?
Ans:
$#
17. How to add user in Solaris/Linux?
Ans:
useradd command
18. What does sudo stand for in Linux systems?
Ans:
Abbreviation of sudo is "substitute user do" (some people will abbreviate it as "super user do"), which allows users to run programs with the security privileges of another user, by default the superuser.
1. What’s the difference between soft link and hard link?
Ans:
A symbolic (soft) linked file and the targeted file can be located on the same or different file system while for a hard link they must be located on the same file system, because they share same inode number and an inode table is unique to a file system, both must be on the same file system.
2. How you will read a file from shell script?
Ans:
while read line
do
echo $line
done < file_name
3. What’s the use of umask?
Ans:
Will decide the default permissions for files.
4. What is the default value of umask?
Ans:
022
5. What is crontab and what are the arguments?
Ans:
The entries have the following elements:
field allowed values
----- --------------
minute 0-59
hour 0-23
day of month 1-31
month 1-12
day of week 0-7 (both 0 and 7 are Sunday)
user Valid OS user
command Valid command or script
? ? ? ? ? command
| | | | |_________day of the week (0-6, 0=Sunday)
| | | |___________month (1-12)
| | |_____________day of the month (1-31)
| |_______________hour (0-23)
|_________________minute (0-59)
6. How to find operating system (OS) version?
Ans:
uname –a
7. How to find out the run level of the user?
Ans:
uname –r
8. What is load average ?
Load Average is the value which represents the load on the system for a specific period of time. Also it can be considered the ratio of the number of active tasks to the number of available CPUs.
run queue length - the sum of the number of processes that are currently running plus the number that are waiting (queued) to run.
9. What is top command?
Ans:
top is a operating system command, it will display top processes which are taking high cpu and memory.
10. How to delete 7 days old trace files?
Ans:
find ./trace –name *.trc –mtime +7 –exec rm {} \;
11. How to get 10th line of a file (by using grep)?
12. (In Solaris) how to find out whether it’s 32bit or 64bit?
13. What is paging?
14. What are huge pages?
Ans:
$?
16. How to find out number of arguments passed to a shell script?
Ans:
$#
17. How to add user in Solaris/Linux?
Ans:
useradd command
18. What does sudo stand for in Linux systems?
Ans:
Abbreviation of sudo is "substitute user do" (some people will abbreviate it as "super user do"), which allows users to run programs with the security privileges of another user, by default the superuser.
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