Bash: How to Remove Specific Characters from String

Often you may want to use Bash to remove specific characters from a string.

There are two common ways to do so:

Method 1: Remove One Specific Character from String

echo "${my_string//a}"

This particular example will remove each occurrence of the character a from the string variable named my_string.

Method 2: Remove Several Specific Characters from String

echo "${my_string//[acr]}"

This particular example will remove each occurrence of the characters a, c and r from the string variable named my_string.

Note that both of these methods use a technique known as shell parameter expansion, which uses the following syntax:

When the value for string is null then matches of pattern are simply deleted.

The following example shows how to use each of these methods in practice.

Example 1: Remove One Specific Character from String in Bash

Suppose we have the following string stored in a variable named $my_string in Bash:

Suppose that we would like to remove each occurrence of the character a from the string.

We can use the following syntax to do so:

my_string="Dallas Mavericks"

echo "${my_string//a}"

The following screenshot shows how to use this syntax in practice:

Bash remove specific character from string

Notice that the output returns the following string:

Each occurrence of the character a has been removed from the string, just as we specified.

Once again, suppose we have the following string stored in a variable named $my_string in Bash:

Suppose that we would like to remove each occurrence of the characters a, c and r from the string.

We can use the following syntax to do so:

my_string="Dallas Mavericks"

echo "${my_string//[acr]}"

The following screenshot shows how to use this syntax in practice:

Bash remove multiple specific characters from string

Notice that the output returns the following string:

Each occurrence of the characters a, c and r have been removed from the string.

Note: Feel free to include as many characters as you’d like within the brackets to remove even more characters from the string.