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BASH

Bash, the Bourne Again Shell, is the default command-line interpreter in most Linux distros.

Hello World

Programmers often learn new languages via learning the hello world program. It’s a simple program that prints the string “Hello World” to the standard output.

Use an editor like vim or nano to create the file hello-world.sh and copy the below lines into it.

#!/bin/bash
echo "Hello World"

Save and quit the file.

You need to make this file executable using the below command.

chmod a+x hello-world.sh

You can run this using any of the below two commands.

bash hello-world.sh
./hello-world.sh

It will print out the string passed to echo inside the script.

Aliases

Append a string after each line

Arithmetic evaluation and errexit trap

Assign Output of Shell Command To Variable

The IFS (internal field separator)

IFS (internal field separator)

Helicopter Animation

List files by size

List files excluding some files

Parse a line from a file

Quotes

Read a file (data stream, variable) line-by-line (and/or field-by-field)

Redirect Output To File, And Still Have It On Screen

Rename multiple files

rev

Run a program in the background