How to compare strings in Bash
bash, string
Solution
Using variables in if statements
if [ "$x" = "valid" ]; then
echo "x has the value 'valid'"
fi
If you want to do something when they don't match, replace `=` with `!=`. You can read more about string operations and arithmetic operations in their respective documentation.
Why do we use quotes around `$x`?
You want the quotes around `$x`, because if it is empty, your Bash script encounters a syntax error as seen below:
if [ = "valid" ]; then
Non-standard use of `==` operator
Note that Bash allows `==` to be used for equality with `[`, but this is not standard.
Use either the first case wherein the quotes around `$x` are optional:
if [[ "$x" == "valid" ]]; then
or use the second case:
if [ "$x" = "valid" ]; then
Problem
How do I compare a variable to a string (and do something if they match)?