How to concatenate two strings in Unix shell scripting

Brief: This example will help you to concatenate two or more strings variable in a bash script. This tutorial helps you with multiple shell script examples of concatenating strings in a shell script.

The first example is a general way to concatenate variables of string. You can simply write all the variable one after another:

#!/bin/bash # Shell program to concatenate two strings in variable str1="Welcome " str2="TecAdmin!" str3=$str1$str2 echo $str3

Output:

Another Example

You can also use += operator to concatenate two strings and store results in the first string.

#!/bin/bash str1="Welcome " str2="TecAdmin!" str1+=$str2 echo $str1

Output:

One More Example

Use another example with one string variable with user input and another fixed strings.

#!/bin/bash # Shell program to concatenate two strings read -p "Enter your name: " name echo "Welcome $str1"

Script execution result:

Using {} with Variables

In some situation, you may face issue while concatenating one string with another string variable as shown in below example. Here you need to use curly braces around variable name.

#!/bin/bash filename="backup" echo "$filename_03132018.sql" ### This will not work echo "${filename}_03132018.sql" ### Correct

Output

You can see that first output if incorrect and second output is correct using {} around variable name.

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