SARVAJANIK COLLEGE OF ENGINEERING AND TECHNOLOGY
COMPUTER ENGINEERING DEPARTMENT
Cyber Security
Practice Questions
, Experiment No: 1
Aim: Study of basic Unix commands
1. Passwd
The passwd utility is used to update user’s authentication token(s).
This task is achieved through calls to the Linux-PAM and Libuser API.
Essentially, it initializes itself as a "passwd" service with Linux-PAM
and utilizes configured password modules to authenticate and then
update a user’s password.
Output:
[root@SAR056 ~]# passwd
Changing password for user root.
New password:
BAD PASSWORD: it is too short
BAD PASSWORD: is too simple
Retype new password:
passwd: all authentication tokens updated successfully.
[root@SAR056 ~]# passwd
Changing password for user root.
New password:
BAD PASSWORD: it is WAY too short
BAD PASSWORD: is too simple
Retype new password:
passwd: all authentication tokens updated successfully.
2.Pwd
Print the full filename of the current working directory.
Output:
[root@SAR056 ~]# pwd
/root
,3.Apropos
apropos searches a set of database files containing short descriptions
of system commands for keywords and displays the result on the standard
output.
Output:
man apropos
[root@SAR056 ~]# apropos gedit
gedit (1) - text editor for the GNOME Desktop
4.Su
Change the effective user id and group id to that of USER.
5.Ssh
ssh (SSH client) is a program for logging into a remote machine and for
executing commands on a remote machine. It is intended to replace rlogin
and rsh, and provide secure encrypted communications between two
untrusted hosts over an insecure network. X11 connections and arbitrary
TCP ports can also be forwarded over the secure channel.
ssh connects and logs into the specified hostname (with optional user
name). The user must prove his/her identity to the remote machine using
one of several methods depending on the protocol version used (see
below).
If command is specified, it is executed on the remote host instead of a
login shell.
Output:
ssh 172.16.1.57
The authenticity of host '172.16.1.57 (172.16.1.57)' can't be established.
RSA key fingerprint is 05:1a:87:7f:39:9b:5a:e8:34:91:db:0d:24:9c:00:83.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '172.16.1.57' (RSA) to the list of known hosts.
root@172.16.1.57's password:
[root@SAR057 ~]# ls
, 170420107045 bin exam Public s17cos23.sql Videos
1 (copy).java Desktop lib s17cos116.sql2.sql share workspace
1.java Documents Music s17cos21.sql Studies
1.java~ Downloads Pictures s17cos239.sql Templates
[root@SAR057 ~]# ssh 172.16.1.56
The authenticity of host '172.16.1.56 (172.16.1.56)' can't be established.
RSA key fingerprint is 05:1a:87:7f:39:9b:5a:e8:34:91:db:0d:24:9c:00:83.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '172.16.1.56' (RSA) to the list of known hosts.
root@172.16.1.56's password:
Last login: Mon Jun 25 11:25:26 2018 from 172.16.1.55
6.Chown
This manual page documents the GNU version of chown. chown changes
the
user and/or group ownership of each given file. If only an owner (a
user name or numeric user ID) is given, that user is made the owner of
each given file, and the files’ group is not changed. If the owner is
followed by a colon and a group name (or numeric group ID), with no
spaces between them, the group ownership of the files is changed as
well. If a colon but no group name follows the user name, that user is
made the owner of the files and the group of the files is changed to
that user’s login group. If the colon and group are given, but the
owner is omitted, only the group of the files is changed; in this case,
chown performs the same function as chgrp. If only a colon is given,
or if the entire operand is empty, neither the owner nor the group is
changed.
Output:
[root@SAR056 Desktop]# ls -l
total 72
drwxr-xr-x. 3 root root 4096 Jun 20 17:40 170420107543
drwxr-xr-x. 4 root root 4096 Jun 11 15:13 8085 Simulator
-rw-r--r--. 1 root root 0 Jun 25 11:43 aayu
-rwxrwxrwx. 1 root root 371 May 22 11:19 AdobeReader.desktop
drwxr-xr-x. 12 root root 4096 May 22 14:56 Cisco-PT-711-x64
drwxr-xr-x. 2 root root 4096 Jun 21 17:44 CO2
-rw-r--r--. 1 root root 43253 Jun 25 11:41 cs_16.odt
-rw-r--r--. 1 root root 288 Jun 18 15:33 s17cos243.sql
COMPUTER ENGINEERING DEPARTMENT
Cyber Security
Practice Questions
, Experiment No: 1
Aim: Study of basic Unix commands
1. Passwd
The passwd utility is used to update user’s authentication token(s).
This task is achieved through calls to the Linux-PAM and Libuser API.
Essentially, it initializes itself as a "passwd" service with Linux-PAM
and utilizes configured password modules to authenticate and then
update a user’s password.
Output:
[root@SAR056 ~]# passwd
Changing password for user root.
New password:
BAD PASSWORD: it is too short
BAD PASSWORD: is too simple
Retype new password:
passwd: all authentication tokens updated successfully.
[root@SAR056 ~]# passwd
Changing password for user root.
New password:
BAD PASSWORD: it is WAY too short
BAD PASSWORD: is too simple
Retype new password:
passwd: all authentication tokens updated successfully.
2.Pwd
Print the full filename of the current working directory.
Output:
[root@SAR056 ~]# pwd
/root
,3.Apropos
apropos searches a set of database files containing short descriptions
of system commands for keywords and displays the result on the standard
output.
Output:
man apropos
[root@SAR056 ~]# apropos gedit
gedit (1) - text editor for the GNOME Desktop
4.Su
Change the effective user id and group id to that of USER.
5.Ssh
ssh (SSH client) is a program for logging into a remote machine and for
executing commands on a remote machine. It is intended to replace rlogin
and rsh, and provide secure encrypted communications between two
untrusted hosts over an insecure network. X11 connections and arbitrary
TCP ports can also be forwarded over the secure channel.
ssh connects and logs into the specified hostname (with optional user
name). The user must prove his/her identity to the remote machine using
one of several methods depending on the protocol version used (see
below).
If command is specified, it is executed on the remote host instead of a
login shell.
Output:
ssh 172.16.1.57
The authenticity of host '172.16.1.57 (172.16.1.57)' can't be established.
RSA key fingerprint is 05:1a:87:7f:39:9b:5a:e8:34:91:db:0d:24:9c:00:83.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '172.16.1.57' (RSA) to the list of known hosts.
root@172.16.1.57's password:
[root@SAR057 ~]# ls
, 170420107045 bin exam Public s17cos23.sql Videos
1 (copy).java Desktop lib s17cos116.sql2.sql share workspace
1.java Documents Music s17cos21.sql Studies
1.java~ Downloads Pictures s17cos239.sql Templates
[root@SAR057 ~]# ssh 172.16.1.56
The authenticity of host '172.16.1.56 (172.16.1.56)' can't be established.
RSA key fingerprint is 05:1a:87:7f:39:9b:5a:e8:34:91:db:0d:24:9c:00:83.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '172.16.1.56' (RSA) to the list of known hosts.
root@172.16.1.56's password:
Last login: Mon Jun 25 11:25:26 2018 from 172.16.1.55
6.Chown
This manual page documents the GNU version of chown. chown changes
the
user and/or group ownership of each given file. If only an owner (a
user name or numeric user ID) is given, that user is made the owner of
each given file, and the files’ group is not changed. If the owner is
followed by a colon and a group name (or numeric group ID), with no
spaces between them, the group ownership of the files is changed as
well. If a colon but no group name follows the user name, that user is
made the owner of the files and the group of the files is changed to
that user’s login group. If the colon and group are given, but the
owner is omitted, only the group of the files is changed; in this case,
chown performs the same function as chgrp. If only a colon is given,
or if the entire operand is empty, neither the owner nor the group is
changed.
Output:
[root@SAR056 Desktop]# ls -l
total 72
drwxr-xr-x. 3 root root 4096 Jun 20 17:40 170420107543
drwxr-xr-x. 4 root root 4096 Jun 11 15:13 8085 Simulator
-rw-r--r--. 1 root root 0 Jun 25 11:43 aayu
-rwxrwxrwx. 1 root root 371 May 22 11:19 AdobeReader.desktop
drwxr-xr-x. 12 root root 4096 May 22 14:56 Cisco-PT-711-x64
drwxr-xr-x. 2 root root 4096 Jun 21 17:44 CO2
-rw-r--r--. 1 root root 43253 Jun 25 11:41 cs_16.odt
-rw-r--r--. 1 root root 288 Jun 18 15:33 s17cos243.sql
