The permission bits of a file noname. can be set to _rws_ _x_ _x by the comma nd.
A. chmod 711 noname
B. chmod go -rw noname
C. chmod 2711 noname
D. None of the above
Explanation :
We can use the command chmod 711 noname, followed by chmod
u+s noname (use ls -1 noname and check). Else use the single command chmod
4711 noname. What is this "s" anyway? Only the super user has the permission
to change /etc/ passwd file. But any user can update it through the
passwd (bin/passwd) command. If you type ls-l /bin/passwd you can see the
user execution bit set to s instead of x).
It is because of this "s". A user can access /etc/passwd
through the passwd command, for which he is not otherwise entitled to.
/bin/passwd has the user execution permission set to 's' because
A. This facility assigns to the user, permissions of the
program owner. temporarily
B. It should allow users who don't have write permission
to /etc/passwd to write to it
C. /etc/passwd is write protected
D. All of these
If one doesn't want anyone else to read or write to a file named datfile, except through a program in a file filex , then he may use
A. chmod u+s filex ; chmod go_rw datfile
B. chmod 4711 filex ; chmod go_rw datfile
C. chmod 4711 datfile ; chmod go_rw filex
Ans D
Shell script is preferable to other forms of programming because it
A. Makes programming task easier
B. Enhances portability
C. Occupies less space
D. All of these
Files that store data in the same format as used in program are called
A. binary files
B. Source file
C. Text file
D. Core
To allow only one user to work with a particular file at a particular time, one has to use
A. Semaphore
B. Critical region
C. Locking
D. Dedicated mode
The differences between malloc( ) and calloc() are:
A. Malloc is used for dynamic allocation of memory, while
cal:1?c can't be used for that purpose.
B. Malloc needs only one argument. while cal loc needs
two.
C. unlike malloc, calloc allocates memory and initializes
it to 0.
D. Both (b) and (c)
The main reasons for the success of pipes are
A. The availability of many filter programs
B. UNIX treats devices as files
C. It provides a 2-way communication channel
D. Both (a) and (b)
Which of the following are not filter programs?
A. date
B. sort
C. cat
D. grep
Ans A
Redirection in pipes can be achieved by using
A. >
B. >>
C. tee
D. lpr
Ans C
