Often you may want to use Bash to count the number of characters in a particular string.
You can use the following methods to do so:
Method 1: Count Total Characters in a String
echo ${#my_string}
This particular example will return the total number of characters in the string variable named my_string.
Method 2: Count Occurrences of Specific Character in String
grep -o "e" <<<"$my_string" | wc -l
This particular example will return the total number of times the character “e” occurs in the string variable named my_string.
Method 3: Count Occurrences of Several Specific Characters in String
grep -o -E "e|a" <<<"$my_string" | wc -l
This particular example will return the total number of times the characters “e” and “a” occurs in the string variable named my_string.
The following examples show how to use each method in practice.
Example 1: Count Total Characters in a String
We can use the following syntax to create a string variable named my_string and then count the total number of characters in it:
my_string="I hope you have a great day"
echo ${#my_string}
The following screenshot shows how to use this syntax in practice:
This returns a value of 27, which tells us that there are 27 total characters in the string.
Note: Spaces count as characters.
Example 2: Count Occurrences of Specific Character in a String
We can use the following syntax to create a string variable named my_string and then count the total number of times the letter “e” appears in the string:
my_string="I hope you have a great day"
grep -o "e" <<<"$my_string" | wc -l
The following screenshot shows how to use this syntax in practice:
This returns a value of 3, which tells us that the letter “e” occurs 3 times in the string.
Example 3: Count Occurrences of Several Specific Characters in a String
We can use the following syntax to create a string variable named my_string and then count the total number of times the letter “e” and “a” appears in the string:
my_string="I hope you have a great day"
grep -o -E "e|a" <<<"$my_string" | wc -l
The following screenshot shows how to use this syntax in practice:
This returns a value of 7, which tells us that the letters “e” and “a” occur a total of 7 times in the string.
Related Tutorials
The following tutorials explain how to perform other common tasks in Bash:
Bash: How to Count Number of Unique Lines in File
Bash: How to List All Files in Folder by Size
Bash: How to List All Files in Folder Without Extension
Bash: How to List All Files Matching a Specific Pattern
