Bash String Concatenation, Methods and Examples

Bash is a powerful scripting language used to automate various tasks in Unix and Linux systems.

One of the most common operations in bash scripting is concatenating strings.

Concatenation refers to the process of combining two or more strings into a single string.

In this post, we will discuss different methods for concatenating strings in bash.

Method 1: Using the + operator

The simplest method of concatenating strings in bash is using the + operator. Here is an example:

string1="Hello"
string2="world"
result=$string1+$string2
echo $result

In this example, we define two strings, string1 and string2.

We then concatenate the two strings using the + operator and store the result in the result variable.

Finally, we print the value of the result variable using the echo command.

However, this method does not work as expected.

When we concatenate the two strings using the + operator, we actually end up with a new string that contains a plus sign (+) between the two original strings.

To fix this, we need to use a different operator.

Method 2: Using the . operator

The correct operator to use for concatenation in bash is the dot (.) operator.

Here is an example:

string1="Hello"
string2="world"
result=$string1$string2
echo $result

In this example, we define two strings, string1 and string2.

We then concatenate the two strings using the . operator and store the result in the result variable.

Finally, we print the value of the result variable using the echo command.

Method 3: Using the += operator

Another method of concatenating strings in bash is using the += operator. Here is an example:

string1="Hello"
string2="world"
string1+=$string2
echo $string1

In this example, we define two strings, string1 and string2.

We then concatenate string2 to the end of string1 using the += operator.

Finally, we print the value of string1 using the echo command.

This method is useful when we want to add a string to the end of an existing string.

Conclusion

In this post, we discussed different methods for concatenating strings in bash.

The dot (.) operator is the correct operator to use for concatenation in bash.

We also saw how to concatenate strings using the += operator.

These methods can be used to perform various tasks in bash scripting, such as generating dynamic file names or building complex strings.