bash contains code example
Example 1: checking if a substring exists in a string bash
string='Haystack';
if [[ $string =~ "Needle" ]]
then
echo "It's there!"
fi
Example 2: bash substring test
#!/bin/bash
STR='GNU/Linux is an operating system'
SUB='Linux'
if grep -q "$SUB" <<< "$STR"; then
echo "It's there"
fi
Example 3: bash substring test
#!/bin/bash
STR='GNU/Linux is an operating system'
SUB='Linux'
if [[ "$STR" == *"$SUB"* ]]; then
echo "It's there."
fi