linux test if string exists in file code example

Example 1: linux test if string exists in file

if grep -Fxq "string" file.txt; then 
	echo "Match"
else 
	echo "No match"
fi

Example 2: bash check if string does not exist 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