bash if substr in string 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 check if string in file
Just use grep with flags 'F' (fixed string), 'x' (exact match) and 'q'
(quiet output) in order to check if a word string is in a file
if grep -Fxq "string" file.txt; then #do some code...#; fi