Question

Unix questions, i need help on

Hint: Commands to study to answer this question: predefined shell variables,

and .profile script file, echo

SHELL, HOME, PATH, MAIL and TERM are predefined shell variables. You can use the value of a shell variable in a shell command putting $ in front of it. For example, to display the value of the HOME directory of the user, specify $HOME in the echo command like echo $HOME.

Do not give just the value of the shell variable as answer to questions given below.

1) Display the value of SHELL

2) SHELL contains the pathname of the shell program you are using. With echo command, answer what is the name of the shell program

3) Display the value of HOME

4) With echo command, answer what the HOME value stand for

5) Display the value of PATH

6) PATH contains the list of directories shell searches for the nonbuilt-in command (that is, the executable program file with name same as the command you typed). The directories in the list are separated by : character.

With echo command, answer whether the list contains . (dot or period) and whether the shell searches the current working directory.

7) Display the value of MAIL

8) With echo command, answer where the system stores your emails. Indicate whether it is a directory or file.

9) Display the value of TERM

10) With echo command, answer what is the type of the terminal you are using. Note: The combination of keyboard and monitor is called a terminal. If the value of TERM is xterm, then indicate what xterm stands for. Do not give the answer as xterm.

11) The .profile file is in your login directory. It is a startup shell script file containing shell (UNIX) commands. The system executes the UNIX shell commands in this file each time you login to setup your session environment before shell displays the first shell prompt (which is $ by default). Display the content of .profile file

12) With echo command specify the list of predefined shell variables in the .profile file

Answer 1

# to display the processes for a particular user:
# ps -ef | grep <username>
echo 'Display processes of particular user:'
ps -ef | grep tom

# to display information about processes using long option
# ps -efl | grep <username>
# notice the l is the above command, it stands for extended listing
echo
echo 'Use the long option:'
ps -efl | grep tom

# display all the processes in the system and output using the grep command only the lines containing init
# a: select all processes
# u: select all processes even those of other users
# x: do not control ttys
echo
echo 'Display all processes in system then grep it to show only init:'
ps -aux | grep init

# display pid of init process
echo
echo 'Display pid of init using echo command:'
result="$(pidof init)"
echo "${result}"

---------------------------------------------

Output screenshot:

Display processes of particular user: 1 e 2433? 2 2433 ? 72 71 0 2433? 73 71 0 2433? 00:00:01 /bin/bash 00:00:00 bash test.sh 00:00:0e ps -etf 00:00:0e grep 2 71 Use the long option: - 2433? - 2433? - 2433? - 2433? 00:00:01 /bin/bash 00:00:00 bash test.sh 00:00:00 ps -efl 00:00:0e grep 2 71 1080 θ- 2080 θ- 74 710 80 θ- 75 710 80 θ- Display all processes in system then grep it to show only init: root ss 1 0.0 0.0 77 0.0 0.e 2433 2433 θ:80 θ:00 /init grep init Display pid of init using echo command: