You can use the following syntax to remove a newline from a string in Bash:
my_variable=$(echo $my_variable | tr -d '\n')
This particular example removes all newlines from the string stored in the variable named $my_variable.
Note that the tr operator is used to translate or substitute one pattern for another in Bash.
By using the tr operator with -d we specify that we want all newlines ( \n ) in the string to be deleted.
The following example shows how to use this syntax in practice.
Example: How to Remove Newline from String in Bash
Suppose that we create a variable named $my_variable that contains two newlines:
my_variable=$'hey \nthere \neveryone'
echo "$my_variable"
The following screenshot shows how to use this syntax in practice:

Suppose that we would like to remove each newline from the string.
We can use the following syntax to do so:
my_variable=$(echo $my_variable | tr -d '\n') echo "$my_variable"
The following screenshot shows how to use this syntax in practice:

When we use the echo command to display $my_variable we can see that all of the newlines have been removed from the string.
By using the command tr -d ‘\n’ we are able to delete all newlines from the original string.
Related Tutorials
The following tutorials explain how to perform other common tasks in Bash:
Bash: How to Replace Newline with Comma
Bash: How to Replace Text in String
Bash: How to Replace Special Characters in String
Bash: How to Replace Multiple Characters in String
