You can use the following methods to replace special characters in a string in Bash:
Method 1: Remove everything except letters
echo $my_string | sed "s/[^[:alpha:]]//g"
This particular example will remove all characters except letters from the string variable named $my_string.
Method 2: Remove everything except letters and numbers
echo $my_string | sed "s/[^[:alnum:]]//g"
This particular example will remove all characters except letters and numbers from the string variable named $my_string.
The following examples show how to use each method in practice.
Example 1: Remove Everything Except Letters in String in Bash
Suppose that we would like to use Bash to remove everything from a string except for alphabetical letters.
We can use the following syntax to do so:
$my_string="4P%enny$)~^Lane#-3!"
echo $my_string | sed "s/[^[:alpha:]]//g"
The following screenshot shows how to use this syntax in practice:
Notice that all characters except for alphabetical letters have been removed from the string.
The original string was: 4P%enny$)~^Lane#-3!
The new string is: PennyLane
Example 2: Remove Everything Except Letters and Numbers in String in Bash
Suppose that we would like to use Bash to remove everything from a string except for alphabetical letters and numbers.
We can use the following syntax to do so:
$my_string="4P%enny$)~^Lane#-3!"
echo $my_string | sed "s/[^[:alnum:]]//g"
The following screenshot shows how to use this syntax in practice:
Notice that all characters except for alphabetical letters and numbers have been removed from the string.
The original string was: 4P%enny$)~^Lane#-3!
The new string is: 4PennyLane3
Related Tutorials
The following tutorials explain how to perform other common tasks in Bash:
Bash: How to Replace Text in String
Bash: How to Replace Specific Line in File
Bash: How to Replace Multiple Characters in String
