Replace string in file

# replace and write edited version into new file

sed 's/oldstring/newstring/g' file.txt > new_edited_file.txt

# to use with Linux pipe |

cat file.txt | sed 's/oldstring/newstring/g' > new_edited_file.txt

# edit directly in original file: replace original file with new edited version (option -i)

sed -i 's/oldstring/newstring/g' file.txt