1) What is meant by passwd file?
A)
This file maintains each and every user information with 7 fields. The 7 fields
are Username:passwd:uid:gid:fullname:home:shell.
2) What is Shell?
A)
Shell is a command line interpreter. Shell acts as an interface between user and the kernel.
3) What is Kernel?
A)
Kernel is core part of unix o/s. It is a group of hundreds of system calls.
4) What are different flavours of unix o/s?
A) Any
operating system designed based on unix kernel called as flavour of unix. The
following are some flavours of unix
Linux
---- Red Hat
Sun
solaris --- Sun Microsystem
IBM-AIX
----- IBM
Hp-ux
----- HP
Sco-unix
----- santa crus operations
IRIX------
Silicon Graphics.
5) What are the
different security features in Unix?
1.
Password protection.
2. File permissions.
3. Encryption.
6) What’s the command to find out today’s
date?
A) date
7) What’s the command to find out users on
the system?
A) who
8) How do you find out the current
directory you’re in?
A) pwd
9) What is the command to see the location
of command?
A) Whereis
<commandname>
10) How do you find out your own
username?
A) Whoami
(or) logname
11) How to close the current user account?
A) exit
12) How to create empty file?
A) Touch
<filename>
13) How do you remove a file?
A) Rm
<filename>
14) How
to join multifile files vertically?
A) Cat file1
file2 file3 ……
15) The
file for which we do not have write permission can be deleted using the command?
A)
rm -f <filename>
16) How do you remove a directory and its
subdirectories ?
A) rm –rf
<directoryname>
17) How
to rename a file?
A) Mv
<filename>
18) How
to copy multiple files and directories into some other directory?
A) cp -r source_directory destination_directory
A) cp -r source_directory destination_directory
19) How to see hidden files?
A) Ls –a
20) How to see files and subdirectories
files recursively?
A) Ls –R
21) How to see files in long list format
page wise?
A) Ls –l
| more
22) How
to identify whether a file is normal file or directory?
A) $ls -l filename/directoryname
A) $ls -l filename/directoryname
if the
first digit is - then it is file,
if it is
d then it is directory file
23)
What is the difference between "ls -r" and "ls -R"?
A)
ls -r lists the files in reverse alphabetical order... whereas ls -R lists the
files and directories recursively
24) The
difference between a soft link and a hard link?
A) 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.
A) 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.
25) what
are the different commands used to create files?
A) 1.touch
- to create empty files (e.g) - touch <filename>
2.vi
<filename>
3. cat>filename
26) List some wild card characters?
? -à Iit matches any single character
* -à It matches zero or more characters
[] -à It matches any single character in
given list
. -à It matches any single character except enter key character
27) what is the
output of the follwing command : ls [a-mno-r]*
A)
list all the files in the current directory starting alphabet
is between a to m or n or between o to r
28) How do you count words, lines and
characters in a file?
A) Wc <filename>
29) which
command is used to identify the type of the file?
A) file
A) file
30) "grep"
means
A)
Globally search a regular expression and print it
31) How do you search for a string inside a
given file?
A) grep
string filename
32) How do you search for a string inside
a current directory?
A) grep
string *
33) How do you search for a string in a directory with the subdirectories recursed?
A)
grep -r string *
34) Difference
between grep, egrep and fgrep
grep : does not accept more then one
expression
egrep : accepts more than one pattern for
search. Also accepts patterns from a file.
fgrep : accepts multiple patterns both from
command line and file but does not accept regular expressions only strings. It
is faster than the other two and should be used when using fixed strings.
35) What are line
patterns?
^ -à start of the line
$ -à End of the line
36) How to search
empty lines in a given file?
A)
Grep “^$” <filename>
37) How to count no
of blank lines in a file?
A) Grep
–c “^$” <filename>
38) How to remove Empty lines form a given
file?
Grep
–v “^$” filename > temfilename
Mv tempfilename
filename
39) What is pattern to search 4 digit word
in a file?
A) Grep
“\<[0-9] [0-9] [0-9] [0-9]\>” filename
40) What is pattern to search the line
having only three characters?
A) Grep
“^…$” filename
41) What is pattern to display lines ending
with “$” character in a given file?
A) Grep
“\$$” filename
42) How to display 2 and 4 th fileds from a
given file if the delimetr is “:”?
A) Cut
–d”:” –f 2,4 filename
43) How to display unique lines from a
given file?
A) Sort
–u filename
44) How to eliminate completely duplicate
lines from a given file?
A) Uniq
–u filename
45) How to remove all duplicate lines from
a file?
Uniq
–u filename > tempfilename
Mv tempfilename
filename
46) How to delete “hello” word from a given
file?
A) Sed
“s/hello//” filename
47)How to compare two files are same or
not?
A) Cmp
48) How to display the first 10 lines from
a file?
A) Head -10
filename
49) Write a one line
command to convert all the capital letters of a file "test" into
lower case?
A)
cat filename | tr "[A-Z]"
"[a-z]"
50) The pipeline to
list the five largest files in the current directory is
A) ls -l | tr -s ' ' |
sort -t ' ' -fnr +4 -5 | head –5
51) The pipeline to
find out the number of times the character ? occurs in the file is
A) tr -dc '?' < file | wc -c ( Delete all the characters except ? and
then make a word count.)
52) How to count
total no. of users working in the system?
A)
Who | wc –l
53) How to display
the lines from 5 to 10 from a given file?
A)
Head -10 filename | tail +5
54) what will be
output of following command?
echo “Tecnosoft”
| wc –c
A) 9
55) What is the
default umask?
A)
022
56) What is the
default permission for File & Directory ?
The
Default privileges for file : 644
The
default privileges for directory : 755
57) What UNIX command will control the
default file permissions when files are created?
A) Umask
58) Explain the read, write, and execute permissions on a UNIX directory.
Read allows you to see and list the directory contents.
Write allows you to create, edit and delete files and subdirectories in the directory.
Execute gives you the previous read/write permissions plus allows you to change into the directory and execute programs or shells from the directory.
A) Umask
58) Explain the read, write, and execute permissions on a UNIX directory.
Read allows you to see and list the directory contents.
Write allows you to create, edit and delete files and subdirectories in the directory.
Execute gives you the previous read/write permissions plus allows you to change into the directory and execute programs or shells from the directory.
58) What is chmod, chown and chgrp?
Chmod
: It is used for to change permissions on files
Chown
: It is used for to change ownership of a file
Chgrp
: It is used for to change group of the file
59) If the owner
doesn’t have write permission on a file, but his/her group has, can he/she edit
it?
A)
No. He/she can’t, because the owner's permission overrides the group's.
60) To see list of files and directories
,what permission required?
A) Read
permission
61) What are PIDs?
A) They
are process IDs given to processes. A PID can vary from 0 to 65535.
62) How do you list currently running
process?
A) ps
63) How do you stop a background process?
A) kill pid
64) How do you find out about all running
processes?
A) ps -ag
65) How do you stop all the processes,
except the shell window?
A) kill 0
66) How do you fire a process in the
background?
A) ./process-name &
67) What does the
command "kill -9 $! " do?
A)
kills the last background process
68) if there is a
process u want to run even after exiting the shell what is the
command used?
A)
Nohup
69) which command
will get executed even after you log out?
A) Nohup
70) which signal
cannot be trapped?
A)
kill –9
71) How
to redirect standard error to a file? Answer
A) 2> filename
A) 2> filename
72)
What does the top command display?
Top command displays the current amount of memory occupied
by the currently executing processes and the details. In addition to memory usage top command displays CPU usage and process details
73) What is the command to send message to
all users who are logged in?
A)
Wall
74) What is the
command to send mail to other user?
A)
Mail username
75) How to open
secondary mail box?
A)
Mail -f
76) What do you do
if you don't want to be interrupted by other users' messages?
A)
mesg n
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