Массовая замена

touch file{1..10}.txt

for i in file*.txt; do echo test > ${i};done

for i in file*.txt; do sed -i 's/test/myword/g' ${i};done

[~]: cat file*.txt 
myword
myword
myword
myword
myword
myword
myword
myword
myword
myword

grep -lr '../' your_path | xargs sed -i '/'