For easy reference to BASH scripting, check out devhints.io/bash
create a script that prints:
Hello World
Answer
#!/bin/bash
echo "Hello World"
create a script that prints:
Hello $username, it is $HH:MM" as terminal output
Answer
#!/bin/bash
echo "Hello $(whoami), it is $(date +"%H:%M")"
create a script that prints:
"My git editor: _"
"My default shell: _"
Answer
#!/bin/bash
echo "My git editor: $GIT_EDITOR"
echo "My default shell: $SHELL"
create a script that prints:
Name of the script: _
First Argument: _
All arguments: _
Current PID: _
Answer
#!/bin/bash
echo "Name of the script: $0"
echo "First argument: $1"
echo "All arguments: $*"
echo "Current PID: $$"
create a script that replaces the word "world" with the word "planet" from the sentence "hello world". See parameter expansion
Answer
#!/bin/bash
string="hello world"
echo ${string/world/planet}
create a script that counts from 1-10. Use a c-like for loop or a range or both!
Answer
#!/bin/bash
# c-like loop
for ((i = 1 ; i <= 10 ; i++)); do
echo $i
done
# iterate over a range
for i in {1..10}; do
echo $i
done
create a script that defines an array of animals and prints:
Number of animals: _
Second animal: _
All animals: _
All animals having removed the second animal: _
Answer
#!/bin/bash
Animals=('dog' 'cat' 'sheep' 'elephant')
echo "Number of animals: ${#Animals[@]}"
echo "Second animal: ${Animals[1]}"
echo "All animals: " "${Animals[@]}"
unset Animals[1]
echo "All animals having removed the second animal: " "${Animals[@]}"
create a script that creates a dictionary of different music genres and an example musician. Then print out your dictionary.
For more info on declare see bash declare
Answer
#! /usr/bin/env bash
# I've used /usr/bin/env bash here to use the latest downloaded version of bash that I have installed and set as my SHELL of choice in MacOS
declare -A genres
genres[blues]="B.B. King"
genres[hiphop]="Snoop Dogg"
genres[punk]="Sex Pistols"
genres[pop]="Britney Spears"
echo "${genres[@]}"
create a script that prints out whether a string is empty or not. For bonus points, takes this as a command argument. See Bash Conditional Expressions
Answer
#!/bin/bash
string=$1
if [[ -z "$string" ]]; then
echo "the string is empty"
else
echo "the string $string is not empty, duh"
fi
create a script that prints out whether a file exists or not. For bonus points, takes this as a command argument and confirm it's set. See Bash Conditional Expressions
Answer
#!/bin/bash
file=$1
if [[ -z "$file" ]]; then
echo "you must input a file name as an argument: ./fileExists.bash FILE"
fi
if [[ -f $file ]]; then
echo "file $file exists!"
else
echo "file $file does not exist"
fi
create a function that takes an argument and prints it as part of a sentence.
Answer
#!/bin/bash
helloFunc () {
echo "You have my attention, $1"
}
helloFunc "do I have yours?"
create a script that traps a SIGINT and prints a message instead. Be sure to also print your PID or press ctrl-T to get the PID of a running process
You can then kill the process like so: kill PID
Answer
echo $$
while true; do
trap 'echo "SIGINT caught!"' SIGINT
done