Escape sequences

An escape sequence is a group of character(s) that does not represent its actual value when it is used as a string literal. Some of the escape sequences are listed below:

Shell substitutes an escape sequence with its actual value.

Example:

In this shell script, firstly we have used an echo command to print a string. Note that we have used an escape sequence ( \n ) at the end of the string. It will add a new line character after printing the string.

#!/bin/sh

// Print the string
echo -e "Hello World! \n"
  
// Print the string
echo -e "Hello w3wiki"

Output:

There are certain expressions that convey special meanings. In other words, they are not what they look like. A shell carries out substitution whenever it encounters such expressions. Hence, substitution is defined as a mechanism carried out by a shell in which it substitutes the value of an expression with its actual value.