Bash: String Variables

String variables are used to store and manipulate text in Bash scripts.

Defining String Variables

Basic variable definition

my_string="Hello World"

To define a string variable, use name="value". Note that there should be no spaces around the equals sign.

Accessing and Printing String Variables

Accessing a variable

echo $my_string

To use the value stored in a variable, precede its name with a dollar sign $. The echo command prints the value to the terminal.

Concatenating Strings

Combining variables and strings

full_name="John Doe" echo "My name is $full_name"

Bash automatically concatenates adjacent strings and variables. You can combine multiple variables or mix them with regular text inside double quotes.

Getting Length of a String

Find the length of a string variable

 my_string="Hello World"
 echo ${#my_string}

To get the length of a string stored in a variable, use ${#variable_name}. This returns the number of characters in the string.

Splitting a String into an Array

Splitting a string by a delimiter

 my_string="apple,banana,cherry"
 IFS=',' read -ra fruits <<< "$my_string"
 echo "${fruits[0]}" # apple
 echo "${fruits[1]}" # banana

To split a string into an array, set the IFS (Internal Field Separator) to your delimiter and use read -ra to assign the words read to sequential indices of the array fruits.

Exporting String Variables

The `export` keyword

export my_variable="Some Value"

The export keyword makes a variable available to child processes or scripts. Without export, a variable is only available in the current shell session.