There are some subtle differences though:

#!/bin/bash

eg=whatever

if [ $eg == what* ]; then   # file glob test
    echo '[]'
fi

if [[ $eg == what* ]]; then   # pattern match test
    echo "[[]]"
fi      

Unless there is a file called "whatever" in the current directory, the first test will not pass.

There are some subtle differences though:

#!/bin/bash

eg=whatever

if [ $eg == what* ]; then   # file glob test
    echo '[]'
fi

if [[ $eg == what* ]]; then   # pattern match test
    echo "[[]]"
fi      

Unless there is a file called "whatever" in the current directory, the first test will not pass, because the match is against a file glob of the current directory contents, whereas the second one is an actual string pattern match.

There are some subtle differences though:

#!/bin/bash

eg=whatever

if [ $eg == what* ]; then   # file glob test
    echo '[]'
fi

if [[ $eg == what* ]]; then   # pattern match test
    echo "[[]]"
fi      

Unless there is a file called "what[something]" in the current directory, the first test will not pass.

There are some subtle differences though:

#!/bin/bash

eg=whatever

if [ $eg == what* ]; then   # file glob test
    echo '[]'
fi

if [[ $eg == what* ]]; then   # pattern match test
    echo "[[]]"
fi      

Unless there is a file called "whatever" in the current directory, the first test will not pass.