Which of the following special shell variables is used to process number of the last background job ?

A. grep
B. tail
C. head
D. cat

A. executable permission only
B. write and executable permissions
C. both read and executable permissions.
D. both read and write permissions

A. ls -l
B. ls -x
C. ls -F
D. ls -a

A. lc
B. wc – l
C. cl
D. count

A. chmod -R a+x progs
B. chmod -R 222 progs
C. chmod -1 a+x progs
D. chmod -x a+x progs

A. nm
B. nu
C. ic
D. li