When user creates a file or directory it will be created
with permission. The default value is 022.
If we create a file or directory the file will be created
with 755 permission.
The calculation is the difference between 777 and the
umask value.
ie. 777-022=755.
If umask is 022 then
Owner will have read, write, execute permissions
Group will have read, execute permissions
Others will have read, execute permissions
How will you delete last ten days records in OS level?
$ find . –mtime -10 exec rm {} \
What is RPM? How will you install RPMS?
RPM Package Manager (originally Red Hat Package Manager,
abbreviated RPM) is a package management system.
$ rpm -Uvh rpmname.rpm
How will you find how many users were connected to a database named “sss” from linux level?
ps –ef|grep –i local|grep sss
How will you get the count of all arguments that is passed in a Shell script?
echo $#
How to check whether the last command executed successfully or not?
Echo$?
if the result is 0(zero) then the command is successfully
executed else if the number is from 1 to 255 it is failed.
From Linux how will you find how many users were connected to the database “sakthi”?
ps -ef|grep -i local|grep -i sakthi|wc -l
How will you view Alertlog file from different directory?
tail -f /home/oracle/db/bdump/alertlog.log
How will you see all the arguments in shell script?
echo $*
How will you configure host name and ipaddress?
Connect to root user and use neat command to add the hostname
and ipaddress. Then restart the network service using
# service network restart
In /etc/hosts add the ipaddress and hostname.
How will execute a shell script in background?
./script.sh &
or
nohup ./script.sh &
which will create a nohup.out in the current directory.
Where will you find the OS level errors?
In /var/log/messages and
$ dmesg
How to view last 15 lines of a file?
$Tail -15 filename
How to copy a folder from one server to another?
First compress the folder using tar command
$tar -zcvf directory_name.tar.gz directory_name
Scp oracle@192.168.1.140:/home/sss/directory_name.tar.gz
oracle@192.168.1.130:/home/oracle/sss/
or
using FTP you can transfer a file
or using third party utilities like winscp, Wsftp etc.
How to edit the crontab? How will you schedule on a file January 26 10:30 am?
crontab -e Edit your crontab file, or create one if it
doesn’t already exist.
crontab -l Display your crontab file.
crontab -r Remove your crontab file.
crontab -v Display the last time you edited your crontab
file
Jan 26 10:30 am assign one job in crontab
30 10 26 1 * . text.sh
How to find the size of a directory and a file?
$du –sh directory_name
$ls -lrth filename
How will you find the modified the files in a home directory?
$find $HOME –type f –mtime 0
$find ~ –type f –mtime 0
What is Chmod –R?
chmod -R 755 directory (-R set permissions recursively
, ie changes the permission to current directory,sub direstory and files)
How will you find obsolete path of “sqlplus”?
$which sqlplus
$type sqlplus
What are the Compress commands?
Gzip
Zip
Tar
Compress
cpio
