Scripting

Question 1

What is the syntax for the first line of a linux script?

Answer 1

!#/bin/bash

tells computer what program to use as interpreter

Question 2

What is the linux command to change a file from read only to executable?

Answer 2

chmod +x

Question 3

What denoted a variable in a linux bash script?

Answer 3

<var>=</var>

$<var> to call variable</var></var>

Question 4

How do you pass in variables to a linux bash script?

Answer 4

$1

$ followed by number is substituted by parameters passed into script

Question 5

What is the syntax that forms an if statement in bash scripting?

Answer 5

if [ ]
then
fi

*fi must be used to close the statement block

Question 6

What is the syntax that forms a for loop in bash scripting?

Answer 6

for in
do
done

*done must be used to close loop block

Question 7

What are the built in command line script editors in linux?

Answer 7

pico

nano

Question 8

What is the syntax to substitute a command to be evaluated by the shell and return its output?

Answer 8

`` - legacy: i.e ls will substitute value of ls

$() - modern: i.e $(ls) will substitue value of ls

Question 9

What is the syntax to disregard errors in a bash script?

Answer 9

> /dev/null 2>&1

errors get sent to a void which disregards anything put in it

Question 10

What is the syntax to see the built in error exit code?

Answer 10

$?

can query $? to see if an error occurred
will be 0 if no errors