Advanced Bash Scripting: Part 1 🔥

Become a Bash Scripting Ninja 🥷!

source: https://bashlogo.com/

Hello, World! Do you use command-line frequently? Or find yourself writing scripting Bash often? If your answer is yes, then this blog (more like cheat sheet!) is just what you were looking for because I’ll be providing you with some cool tricks that I’ve learned while diving deeper into the Bash scripting language. Let’s get straight into it!

Special characters and operations

echo ~+ # same as "echo $PWD"
echo ~- # same as "echo $OLDPWD"
echo $* # all positional arguments passed to script, function, etc
echo $@ # same as above

:  # means no operation (no-op)

# ternary operator in Bash!
variable=$(( 1>2 ? 1:2 ))
echo $variable
# 2

# get last positional parameter
last_arg=${!#}
echo $last_arg
# ./script.sh 1 2 3 4
# 4

# if `username` not set, set default value to output of `whoami` command
echo ${username:-$(whoami)}
# output of `whoami` command

# if variable is set, use alternative value
path=/some/path
path=${path:+/some/alternative/path}
echo $path
# /some/alternative/path

Generating all the characters for a valid base 64 / hex string

b64_chars=( {a..z} {A..Z} {0..9} + / = )
echo $b64_chars
# a b c d e f g h i j k l m n o p q r s t u v w x y z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 0 1 2 3 4 5 6 7 8 9 + / =…