Single quotes (literal strings) in Bash Scripting

Introduction

Single quotes let you write text exactly as it is, without any changes or special meanings.

When you want to print a message exactly as you typed it.

When your text has special characters like $ or \ that you don't want to be treated specially.

When you want to store a fixed string in a variable without any substitutions.

When you want to avoid accidental command or variable expansions inside your text.

Syntax

Bash Scripting

echo 'your text here'

Text inside single quotes is taken exactly as written, no variables or commands run inside.

You cannot put a single quote inside single quotes directly; you need tricks to do that.

Examples

Prints the exact text Hello, world! without any changes.

Bash Scripting

echo 'Hello, world!'

Prints My name is $name literally, not My name is John.

Bash Scripting

name=John
 echo 'My name is $name'

Shows that $ and backslash are not treated specially inside single quotes.

Bash Scripting

echo 'Special chars like $ and \\ stay as is'

Sample Program

Shows how to store and print a string with a single quote inside using escaping and closing/reopening single quotes.

Bash Scripting

#!/bin/bash

message='It'\''s a sunny day!'
echo "$message"

literal='It'\''s a sunny day!'
echo "$literal"

Important Notes

Inside single quotes, everything is literal except you cannot directly include a single quote.

To include a single quote inside single quotes, close the quotes, add an escaped single quote, then reopen the quotes: 'It'\''s'.

Double quotes allow variable expansion, but single quotes do not.

Summary

Single quotes keep text exactly as you write it.

No variables or commands run inside single quotes.

Use special tricks to include single quotes inside single-quoted text.