Code / Linux

Question 1

What is the Unix command to generate a new SSH key pair?

Answer 1

$ ssh-keygen

Question 2

What is the command to Grant Administrative Privileges to a new user so that user can run superuser commands by adding sudo before the command?

Answer 2

$ usermod -aG sudo [username]

Question 3

What is the command to test nginx’s configuration?

Answer 3

$ sudo nginx -t

Question 4

What are the commands to list all the users in linux?

Answer 4

Local user information is stored in the /etc/passwd file.
$ less /etc/passwd

Displays entries from databases configured in /etc/nsswitch.conf file, including the passwd database, which can be used to query a list of all users.
$ getent passwd

Question 5

What is the command to create a user in linux?

Answer 5

Use the -m (–create-home) option to create the user home directory as /home/username:

$ sudo useradd -m username
$ sudo passwd username

Question 6

What is the PostgreSQL connection url?

Answer 6

postgresql://username:password@localhost/db_name

Question 7

Reset git cache to untrack files in .gitignore

Answer 7

$ git rm -r –cached .
$ git add .
$ git commit -m “.gitignore is now working”

Question 8

Change git upstream url

Answer 8

$ git remote set-url new-upstream-url

Question 9

Commands for getting status, starting, stoping, restarting postgres?

Answer 9

$ sudo /etc/init.d/postgresql-8.3 status
$ sudo /etc/init.d/postgresql-8.3 start
$ sudo /etc/init.d/postgresql-8.3 restart
$ sudo /etc/init.d/postgresql-8.3 stop

Question 10

Command for listing all the services?

Answer 10

$ service –status-all

Question 11

Command for describing a table in postgres?

Answer 11

db_name=# \d+ table_name;

Question 12

How to choose a database in postgres cli?

Answer 12

postgres=# \c database_name;

Question 13

How to list tables in current database in postgres cli?

Answer 13

db_name=# \dt