sed is a linux command that can replace characters and words in a file very easy!
Syntax:
sed -i 's/word/newword/g' file.txt
It means:
replace all “word” with “newword” in the file called “file.txt”. Be aware! The option -i means that you will manipulate the file file.txt on-the-fly!
If you are not sure, skip the -i option.
Short and useful. A quick tip: sed -i.bak keeps a backup while editing in place, which is handy when you’re not 100% sure about the pattern.