Shell by Example: Quoting POSIX 

#!/bin/sh

Quoting in shell scripts controls how special characters are interpreted. Understanding quoting is essential for writing correct shell scripts.

There are three types of quoting: single quotes, double quotes, and backslash escaping.

 

name="World"

Double quotes preserve most characters literally but allow variable expansion and some escapes.

 

echo "Hello, $name!"

Single quotes preserve ALL characters literally. No variable expansion happens inside single quotes.

 

echo 'Hello, $name!'

Use single quotes when you want literal text with no interpretation of special characters.

 

echo 'The variable is written as $name'
echo 'Backslashes are literal: \n \t'

Double quotes are needed when variables might contain spaces or special characters.

 

filename="my file.txt"
echo "Processing: $filename"

Without quotes, the shell would split on spaces. This is called word splitting.

The backslash escapes single characters.

 

echo "She said \"Hello\""
echo "Path: C:\\Users\\name"
echo "Dollar sign: \$100"

You can mix quoting styles in the same string.

 

echo "It's a $name"
echo 'Say "Hello"'

Escape sequences like \n and \t are NOT interpreted in double quotes:

 

echo "Line 1\nLine 2"   # Note: \n is NOT interpreted here (use echo -e or $'...')
echo "Tab:\tseparated"  # Note: \t is NOT interpreted here (use echo -e or $'...')

For reliable newlines, use literal newlines (shown below) or printf. Note: $‘…’ works in bash but is not POSIX.

 

echo "Line 1
Line 2"

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by Jose Diaz-Gonzalez | inspired by Go by Example | source