103.1 Work on the Command Line

Question 1

What are four shells

Answer 1

• bash (bourne again shell)
• csh (C style syntax)
• ksh (Bourne Shell + C shell)
• zsh (Bash shell + Korn shell)

Question 2

How do you turn on debugging?

Answer 2

set -x

To turn off set +x

Question 3

Write a function that return “yo” to the screen. Then remove it.

Answer 3

function yo() {
  echo yo
}

unset -f yo

Question 4

How do you export a variable to the current shell and any new shells started from the current shell?

Answer 4

export YO=yo

Question 5

What is the environment variable that contains the number of lines that the .bash_history will contain.

Answer 5

HISTFILESIZE

Question 6

File located in the user’s home directory that contains the previously run commands.

Answer 6

.bash_history

Question 7

How do you view the bash history?

Answer 7

history

Question 8

What are the 8 sections of the man pages

Answer 8

S1 - Executable programs or shell commands
S2 - System Calls - Functions provided by the kernel
S3 - Library calls - Functions within program libraries
S4 - Special Files - Typically those found in /dev
S5 - File formats and conventions - for exaple /etc/passwd and other configuration files
S6 - Games
S7 - Miscellaneous items and conventions (man regex)
S8 - System administration commands - only for root

Question 9

How do you search the man pages for a keyword?

Answer 9

apropos
or
man -k