Often you may want to use Bash to check if a string starts with a specific value.
You can use the following methods to do so:
Method 1: Check if String Starts with Specific Value
if [[ $my_string == A* ]]
then
echo "String starts with A"
else
echo "String does not start with A"
fi
This particular example will check if the string variable named my_string starts with “A” and outputs the appropriate result.
Method 2: Check if String Starts with One of Several Specific Values
if [[ $my_string =~ ^(A|B) ]]
then
echo "String starts with A or B"
else
echo "String does not start with A or B"
fi
This particular example will check if the string variable named my_string starts with “A” or “B” and outputs the appropriate result.
The following examples show how to use each method in practice.
Example 1: Check if String Starts with Specific Value in Bash
Suppose we have a string variable named employee_ID that contains the ID of some employee at a particular company and we would like to check if it starts with “M” or not.
We can use the following syntax to do so:
employee_ID="Manager23350"
if [[ $employee_ID == M* ]]
then
echo "String starts with M"
else
echo "String does not start with M"
fi
The following screenshot shows how to use this syntax in practice:
This returns “String starts with M” since the string variable does indeed start with the letter M.
Example 2: Check if String Starts with One of Several Specific Values in Bash
Suppose we have a string variable named employee_ID that contains the ID of some employee at a particular company and we would like to check if it starts with either “A” or “M”.
We can use the following syntax to do so:
employee_ID="Manager23350"
if [[ $employee_ID =~ ^(A|M) ]]
then
echo "String starts with A or M"
else
echo "String does not start with A or M"
fi
The following screenshot shows how to use this syntax in practice:
This returns “String starts with A or M” since the string variable does indeed start with one of these two letters.
Note: The | operator stands for “or” and the ^ operator stands for “the beginning of string” in regex.
Related Tutorials
The following tutorials explain how to perform other common tasks in Bash:
Bash: How to Count Number of Words in String
Bash: How to Count Number of Characters in String
Bash: How to Count Number of Columns in File
