You can find and replace text on one or multiple file at once using sed RHEL command
sed -i 's/TEXT-TO-FIND/REPLACE-WITH/g' filename.txt
Find and replace text on multiple files with .txt extention
sed -i 's/TEXT-TO-FIND/REPLACE-WITH/g' *.txt
Replace TEXT-TO-FIND and REPLACE-WITH with the text you’re looking for and its replacment
Example:
sed -i 's/thursday/friday/g' weekdays.txt
The above command replaces the word ‘thursday’ with ‘friday’ on file weekdays.txt